Top 13 Email Deliverability Issues & 5 Tips to Fix Them Fast

What if you discovered that nearly half of your emails never reached your recipients? You'd probably feel stressed. Well, this is precisely what happens when you have email deliverability issues. What's worse, the emails that get delivered could end up in the spam folder, or even worse, fail to achieve inbox delivery, ultimately undermining your efforts. While email marketing has many moving parts, ensuring your emails reach your recipients is one of the most crucial elements. If you need help with email deliverability issues, this article will help you quickly identify and resolve the underlying causes to improve your email engagement rates and boost campaign success.

Inframail's email infrastructure solution makes this process easier by helping you to identify and fix deliverability issues so that you can get back to what matters: crafting great emails that engage your audience.

What Is Email Deliverability?

email page - Email Deliverability Issues

Email deliverability is a critical metric that measures how many emails land in the end user's inbox. While email delivery measures how many emails got delivered, deliverability measures how many ended up in the inbox. The average deliverability is 84.2%.

Why is Email Deliverability Important?

Deliverability is critical when it comes to email outreach. Akin to how a runner undergoes checks to ensure fair competition, your email goes through spam filter checks, from authentication to the spam score of templates. Similarly, emails with proper authentication and favorable sender reputations are more likely to pass the spam filter successfully, improving their chances of landing inbox placement.

Obstacles such as incorrect addresses or content issues can delay or disqualify your email (going to spam or bouncing). The goal of every marketer is to see his email make it to the recipient’s inbox. Maintaining a reasonable deliverability rate ensures that The emails you send don’t get lost in the spam folder. You keep a good reputation with the ISPs. You achieve the ultimate goal—conversion.

Why Are Email Deliverability Rules Getting Tougher?

“Google, Yahoo, and many other mailbox providers are getting increasingly frustrated with having to deal with spam,” Al Iverson, industry research and community engagement lead at Valimail, told MarTech. “So you have requirements that are tightening up, meant to make it harder to send unwanted and unsolicited emails.”

How Big is the Spam Problem?

“The latest figure I saw was something like 347,000,000,000 emails sent a day,” Cynthia Price, SVP of Marketing at Litmus, told Martech. “And over half of those, depending on which metrics you look at, are estimated to be spam.”

That’s 173,000,000,000 spam emails a day. “The internet service providers, the Googles and the Yahoos and the Microsofts of the world are trying to do everything they can to hold down the fort and protect our inboxes from mayhem,” said Price.

The Cost of Email Deliverability Failure

According to Mailtrap, the cost of undelivered emails for U.S. businesses is:

$164+ million daily.
$1.1+ billion weekly.
$4.9+ billion monthly.
$59.5+ billion yearly.

Deliverability problems cost more than $15,000 for every million emails sent, according to a report by Validity. “A lot of people don’t understand they have deliverability problems until it’s too late,” said Price. “And, much like a credit score, it takes time to build it back up and to be recognized as a safe sender.”

13 Email Deliverability Issues and How to Solve Them

discussion on issues - Email Deliverability Issues

1. The Dreaded Spam Folder: Why Did My Emails Suddenly Land Here?

Your email marketing campaigns can dramatically drop in deliverability overnight, and one day, you are enjoying a healthy inbox placement rate when suddenly, your following email performance report reveals that most of your emails are going straight to the spam folder. What gives? Email marketing is often at a crossroads as unwanted emails battle for your attention. Not only do emails from spam senders make it to spam, but your business’s emails can also land in the spam.

That's when you have to circle back and see for gaps in infrastructure because that’s where the setup begins.

Infrastructure

IP reputation with Google & Microsoft can be measured by looking at Google Postmaster & SNDS. If your IP reputation has dipped, identify the root cause:

Identify which sender is responsible for the dip if it’s a shared IP.
If it's a dedicated IP, check what content and data were targeted on the day of the dip.

This is because your ESP needs to constantly monitor your IP so it doesn’t get listed, which we do at Mailmodo quite consistently. This helps maintain a good and consistent IP reputation.

End User Response

Avoid investing in third-party databases. Buying an email list may make your job easier, but in hindsight, that’s not the case because your emails reach recipients who share zero affinity with the brand.

As spam traps are not filtered, cleaning pre-bought databases with a tool will only do a little. Also, what happens to users who have uninstalled your app and share a reduced affinity with your brand? Thus, keeping a tab on the end-user response helps ensure deliverability.

Content Reputation

Deliverability issues related to content exist beyond the word FREE or other specific phrases. Let’s say your email campaign is on the receiving end of many spam complaints. As a result, the text in the footer can be a phone number, or your email ID gets cached negatively, causing it to land in spam even when you send it to the right audience segment from a different infrastructure.

The above is one of many instances that profoundly impact the content's reputation. Following best practices such as eliminating URL shorteners like /bit.ly and avoiding map tags, sometimes it’s better to prevent alt and title tags as they don’t impact emails in contrast to how they impact SEOs.

2. Do You Have Sudden Delivery Errors?

To determine delivery errors, you can use Google's Postmaster. The most common reasons include the following:

Temporary rate limits have been triggered because this domain or IP address has been sending traffic at an unusually high rate. The incoming traffic is suspected to be spam, and the incoming email could be spam due to problems with the content.
Attachments in emails that the ISP does not authorize. The DMARC policy of the sender’s domain doesn’t align with the recipient’s.
The sender’s domain and IP reputation are poor. Using Postmaster, you can identify the errors and how they significantly hamper your deliverability.

You can start by following these best practices:

Format emails as per Internet standards.
Don’t send messages without seeking consent, as there’s a possibility that the recipient will mark you spam in the future.
Build on increasing your sending volume slowly.
Verify the sending server’s PTR(pointer) record.

3. A Sudden Dip in Reputation? What Did I Do Wrong?

Let’s say most of your email list comprises gmails’s email addresses. So, by using Postmaster, we can analyze the root cause of the dip in reputation.

Because a dip in reputation is caused by various factors, including:

Have you stopped signing authentication?
Have you changed the content?
Are you experiencing high spam complaints because you have changed the target audience?
Adhering to authentication protocols shows email providers that you have taken all the steps to secure your email systems and demonstrates that you are indeed who you intend to be.

Improving Email Authentication and Security for Better Deliverability

From Postmaster’s dashboard you can gauge the number of emails that have passed the authentication checks through a graph. If there’s any discrepancy, you can see that your authentication sits at 0%. This is the call to fix your authentication problems.

Content is not just the copy but also the subject line, header, design, and use of qualified domain names instead of shortened links. Through unsecured HTTP websites, spammers introduce Trojans and worms and try to hijack websites, and you should switch to a more secure HTTP as it’s encrypted.

4. What Does It Mean If My IP Gets Blacklisted?

Suppose, let’s say, you've been working hard for weeks on crafting the perfect email, and now the results are showing. You're seeing an increase in deliverability rates. Upon reviewing the statistics in your email marketing platform, disappointment washes over you as you observe your deliverability rates plummeting.

This is because there’s an increased chance of your emails getting blacklisted. This can be classified into Real-time blacklists. Domain name server blacklists.

To find out whether you are on the blacklist, go to Mxtoolbox. It’s easy to check using the following steps:

Go to the official service page.
Enter your IP or domain address.
Press Check Blacklist.

Common reasons as to why your IP address is blacklisted can be due to various reasons:

At a minimum, emails have not been authenticated with DKIM & SPF. If you keep sending emails to inactive email addresses, even the best emails will end up in the spam folder sooner rather than later.
Sending volumes are high. Spammers send as many emails as they can, so you should monitor your sending volumes to avoid triggering blacklist suspicions.

Reconsider your sending frequency to prevent the issue. Some users will always complain about spam, and little can be done about it. If your spam complaint rate continues rising, you must find and fix the root cause.

5. Is My Email Sender Reputation So Bad That ISPs Are Blocking My Emails?

The ISPs take many factors into account, and if you are found sending spam emails, most ISPs will stop you from sending emails. In most cases, an ISP gets blocked because of a local policy on the recipient's email server or, in rare cases, because of a reputation issue with the IP address used to send the message. Also, they'll block you if you send email blasts without personalization while having a bad domain and IP reputation will let ISPs block your emails.

Preventing False Positives and Improving Email Deliverability with Proper Email Practices

For instance, if you have used Outlook, you must know that most legitimate emails are mistakenly blocked as threats(false positives).To avoid this, you can request recipients to mark your email as “not junk “and add you to their safe sender list. Also, security administrators enable end users to receive an email digest about quarantined messages.

The key to success in email marketing is discipline. Sending messages in a timely and consistent manner requires a well-planned email cadence. Following best practices and good email etiquette will help you improve your IP and domain reputation and keep your ISPs from blocking you.

6. Bounces Due To Authentication Errors Are No Good

Authentication-related bounces occur when the recipient's mailbox does not accept an email. It is commonly said that “your email bounced.” Bounces are of two types: hard and soft bounces. Authentication errors mainly cause them.

There are several reasons why authentication errors can cause bounces:

It is possible that the recipient's email address does not exist or needs to be corrected, resulting in a rejection.
With double-opt-in signups, you eliminate the possibility of receiving misspelled or nonexistent email addresses.
A soft bounce occurs when the recipient's mailbox is complete and the storage limit has been exceeded.
The email server will reject new messages until space is freed up. In such cases, the recipient must make room for new ones.
The email may be rejected if the sender’s domain is not authenticated. Some email servers require proper domain authentication (e.g., SPF, DKIM, DMARC).
The recipient's email server can block emails from specific sources using endpoint protection services, resulting in bounces. This can be addressed by enabling Branded URLs or authenticating the sending domain.

7. How Do I Check My IP Address Reputation?

If you’ve now tried all of the above steps and have still not identified why you’re going to the spam or junk folder, it’s likely that you’ve taken a hit to your sender reputation score and that blacklisting is now associated with your IP or domain. If the IP address that you’re sending emails from has been associated with spam in some way, it may be on one or more blacklists.

For example, AOL has its IP reputation monitor and rates the sender’s IP reputation as “bad,” “neutral,” and “good.” If your IP reputation is “bad” with AOL, your emails will be filtered out as junk mail or blocked altogether.

The Importance of IP Reputation in Email Deliverability and Spam Prevention

A “neutral” reputation is generally OK. Before checking the content of the email, the filters check the IP address to see if it is white- or blacklisted. If it is whitelisted, your email will be delivered without its content being checked. If the IP has been blacklisted, the email will be “blackholed,” bounced back, or flagged as spam without the content check.

Blackholed emails are not delivered to the user but are saved in a place accessible to administrators in case they are needed later. This approach is often used for emails containing viruses to keep end-users from accidentally opening them.

Testing the IP Address Reputation

You can do a couple of things to test your IP reputation:

1. Send your email through a different mail server or service provider.

For example, if you regularly send emails through your mail server, consider sending them through an email service provider or delivery services such as Amazon SES, SparkPost, Mailgun, or others.

Keep the same subject, sending address, and content. If the email was blocked when sent through your server but is delivered with no problems through an ESP or delivery service, you may have an IP reputation problem.

2. Test your IP against blacklists with the GlockApps IP blacklist checker.

You can set up an automated process of checking your IP against blacklists and be alerted via email, Slack, or Telegram when the IP gets blacklisted. IP reputation monitor checks all major blacklists in the industry and alarms if the IP gets blacklisted.

Suppose the email isn’t delivered using a different server or service provider. In that case, you may have a problem with one of the things listed above, like the sender’s email address/domain reputation or content.

3. Correcting IP Address Reputation Problems.

If you have a blacklisting issue, go through the removal process. The removal instructions are usually stated on the blacklist’s website. It makes sense only if you are sending via your mail server and have control over your sending IP. If you are sending emails via an email service provider or SMTP relay service, they usually use several IPs and de-list blacklisted IPs themselves periodically.

You can also reduce the size of your email list to only send to the most engaged users. Remove anybody who doesn’t regularly open and respond to emails from your list. Then, I send it to only my most active subscribers. This will improve my email metrics with email service providers because it will demonstrate high open rates and low unsubscribe or spam complaints. A smaller number of emails also means a higher chance of getting into the Inbox. It’s not an ideal fix, but it allows you to continue sending regularly with limited results.

4. What if IP Reputation is Beyond Fixing?

This is a miserable and challenging situation. If your IP reputation is killed and nothing helps, you’ll need to acquire a new IP to send from. It may not solve all your deliverability issues because spam filters can associate your reputation with your IP address, domain, or both.

Thus, changing both the IP address (probably by changing ESPs) and the domain would be the best solution, but it is not possible for most companies, as the domain cannot be abandoned. In this case, change the IP, register a new sub-domain using your brand, for example, mail.brand.com, set up a new sending address and authentication records, and begin using best practices to achieve good engagement and reputation.

8. Are You Settling for a Single Opt-in?

Confirmed (or double) opt-in means that, after people select to sign up for your email list, they receive a confirmation email they must use to verify their subscription. Confirmations are great options for a double opt-in.

Not only does a confirmed opt-in help protect you from erroneous signups and spambots, but confirmed opt-in lists see better results with almost every engagement metric, other than the sheer number of sign-ups compared to single opt-in lists. Confirmed opt-in lists are more engaged from the start, and by using confirmed opt-in, you can more effectively build your sending reputation by sending to a more involved and active list.

9. Unclear or Spam-Flagging Subject Lines Are Bad for Deliverability

Your subject line is the welcome mat of your email and, often, issues with subject lines are as simple as this: If your subject line makes your email look like spam, then people and the spam filters ISPs put in place to protect them will probably think that it’s spam.

Avoid ALL CAPITALS, excessive and unnecessary punctuation (!!!), and use symbols and SP$C!AL CH@RCT3RZ sparingly and only when relevant. Also, ensure that your subject lines match the content of your email. No one wants to be promised a trip to a theme park and be at the dentist. An “RE” or “FWD” prefix is misleading when there’s been no such previous contact or email exchange.

Crafting Effective Subject Lines for Better Email Open Rates

Does your email require “urgent action,” and is my offer “exclusive” and “one time only” designations? If not, leave them out. Best practices for the rest of your email copy are also valid for your subject lines.

Be concise, as many email clients may need to correct subject lines with more characters. Use personalization, be creative with your copy, and be transparent with your subscribers about what the email contains.

10. Designing Emails with Too Many Images Is Not Ideal

A historic spam technique was sending emails containing just one image or many images and very little text in HTML emails to bypass spam filters based primarily on spam keywords. Spam filtering is now based much more on sending reputation than content, though the image-to-text ratio still carries some weight with spam filters and is something you’ll want to spend time getting right.

Balancing Images and Text for Effective Email Design

Emails with very little copy and many images, or simply composed of one large image, can be hallmarks of spammers. By composing similar emails, you can risk your email being flagged as spam. Remember, many email clients or devices aren’t configured to display images by default. Suppose your email is composed almost entirely of images a recipient’s email client doesn’t display.

In that case, the content of your email will be unreadable and certainly not something your client can interact with easily. Too many images can look spammy. Instead, design your emails with this in mind and ensure we balance your images and copy so that your email makes sense and engages even if the images are not displayed. I always use alt text for my pictures, so even if they don’t render, your subscribers will have some context for what the photos are.

11. Using URL Shorteners Can Kill Your Deliverability

The use of URL shorteners is a notorious technique used by spammers to hide the nature of URLs they link to and, as such, rank high on reasons spam filters can block your emails, even if the links themselves are legitimate. Avoid using URL shorteners and inserting the full URL link as text in the body of your email.

Instead, create a hyperlink with the appropriate text and ensure all my links go to legitimate domains and are valid and functional. Replacing URL shorteners with clear and attractive CTAs will drive traffic and see more click-throughs on your sends. This is another piece of the sending reputation pie that can further boost your email deliverability.

12. Are You Making It Difficult to Unsubscribe?

While an unsubscribe link must be included in every email sent through Campaign Monitor, we also recommend that it be simple and easy for your recipients to find. Hiding your unsubscribe link in a wall of text with an 8pt font will only frustrate your recipients should they attempt to unsubscribe. In our experience, the more difficult it is to unsubscribe, the more likely your recipients will mark your email as spam.

The Importance of Clear and Accessible Unsubscribe Options

Roku does an excellent job of making its unsubscribe link easy to find. Instead of including it in a large wall of text, it is set apart from the other information so users can see it and click it to remove themselves from the list.

Make your unsubscribe option clear and easily visible, and, better yet, add a permission reminder message to remind people where they signed up or permitted you and point them to unsubscribing if they’re no longer interested in receiving your emails. Your recipients will appreciate this honesty and clarity, and an unengaged recipient choosing to unsubscribe is always preferable to receiving a spam complaint.

13. What Are Spam Traps and Why Are They Bad?

The other reason for being put into spam folders is if you send to spam traps. There are two types of spam traps:

Recycled Email Addresses

Recycled spam traps are email addresses that once belonged to an actual person but have been abandoned for a while. ISPs turn these mailboxes into spam traps, meaning that the mailbox still exists (so you will not see any bounces) but belongs to the ISP rather than a person. These traps catch senders that need to use industry best practices, such as keeping a healthy database by regularly removing bounced or non-engaged contacts.

Artificial Email Addresses

ISPs and spam blocklist providers also create fake email accounts that have never belonged to anyone (and have, therefore, never subscribed to any marketing mailing). These traps are meant to catch senders that buy address lists.

Multiple reasons for hitting spam traps exist:

Your data capture points need to be carefully set up; for example, you do not use double opt-in (DOI).
You try to send to a contact base that is old or has yet to be verified in the last year.
You need to clean up your database of bounces and inactive contacts frequently.
You revalidate bounced email addresses now and then without understanding the bounce reasons.
You buy address lists.

5 Best Practices to Improve Email Deliverability

woman fixing email issues - Email Deliverability Issues

1. Create Good Quality Content for Improved Email Deliverability

Engagement matters in email marketing. When emails sit unopened in inboxes, it signals to ISPs that you’re sending emails recipients don’t want. This hurts your sender’s reputation and email deliverability.

To improve engagement, test your email to ensure it renders as expected. You can use the test in email client features to ensure your email is optimized for mobile devices. Within the email editor, click the bar graph icon to open the email optimizer and review recommendations to improve your email content and deliverability.

2. Use Email Features that Improve Deliverability

Work with your IT team to connect your email-sending domain. Adding a few records to your Domain Name Server (i.e., GoDaddy) confirms that you own the email domain you're using with HubSpot. This makes your emails look more authentic to email filters. If your IT team uses a DMARC policy, update all necessary records. Turn on double opt-in on your HubSpot forms. When this feature is enabled, contacts who submit a form will receive a follow-up email with a link to confirm their subscription.

Enhancing Deliverability with Graymail Suppression

This extra step helps you avoid fake or misspelled email addresses and ensures that all new contacts added to your database actively engage with your content. Turn on graymail suppression in your email settings. Graymail is a term for email that sits unopened in your recipients' inbox, which makes you look like a sender who's sending spam.

This feature uses the Sends since last engagement contact property to automatically exclude contacts not engaging with your emails to improve your email deliverability results instantly.

3. Warm Up Your Email Sending

To ensure consistent delivery and establish a positive reputation with email inbox providers, you should gradually ramp up the volume and frequency of the emails you send. You’ll go through an automated 40-day warm-up period when you purchase the dedicated IP add-on. Your email traffic will be split between HubSpot's shared network and your new IP address. If you opt out of this automated warm-up period, you should manually increase your email volume.

Learn more about IP warm-up here. If you recently migrated to a brand new domain or email service provider, mailbox providers, and ISPs will immediately not recognize the new domain when email is delivered. You should send a few emails first, then gradually increase your email volume over 30 to 60 days. Regularly monitor your sending reputation for continued favorable engagement rates, such as your cumulative click and open rates. Using the Email Health tool, you can check your deliverability performance over the last 30 days.

4. Analyze Email Performance

Use insights from your past email campaigns to improve engagement over time. Review your contact lists regularly to identify outdated email addresses and unengaged contacts. Remove these contacts from your lists to see better email metrics and boost your sending reputation. Email engagements are stored in a series of contact properties that help you identify trends and take action to improve your future email results.

Using A/B Testing to Optimize Email Campaigns

Learn to analyze your email results. Email opens and clicks demonstrate that you're sending your subscribers the right types of content. Spam complaints, high bounce rates, and unsubscribes are hostile email engagements that can damage your email-sending reputation.

Track your results to learn what content resonates with your readers and which contacts you should include in your email campaigns. By varying the send time, subject line, or content of your email, you can run an A/B test on your marketing emails.

5. Perfect Your Opt-In Process

Implementing an opt-in process where subscribers confirm their email addresses after signing up is very important. This helps ensure that the email addresses provided are valid and that your email list of engaged users is complete.

Start Buying Domains Now and Setup Your Email Infrastructure Today

Inframail is revolutionizing cold email deliverability. This platform offers unlimited inboxes at a flat rate, unlike traditional providers, charging per inbox.

With Inframail, users can avoid costly email deliverability issues from using too many inboxes to reach their goals and getting flagged by spam filters.

What Is Email Deliverability?

Email deliverability is a critical metric that measures how many emails land in the end user's inbox. While email delivery measures how many emails got delivered, deliverability measures how many ended up in the inbox. The average deliverability is 84.2%.

Why is Email Deliverability Important?

Deliverability is critical when it comes to email outreach. Akin to how a runner undergoes checks to ensure fair competition, your email goes through spam filter checks, from authentication to the spam score of templates. Similarly, emails with proper authentication and favorable sender reputations are more likely to pass the spam filter successfully, improving their chances of landing inbox placement.

Obstacles such as incorrect addresses or content issues can delay or disqualify your email (going to spam or bouncing). The goal of every marketer is to see his email make it to the recipient’s inbox. Maintaining a reasonable deliverability rate ensures that The emails you send don’t get lost in the spam folder. You keep a good reputation with the ISPs. You achieve the ultimate goal—conversion.

Why Are Email Deliverability Rules Getting Tougher?

“Google, Yahoo, and many other mailbox providers are getting increasingly frustrated with having to deal with spam,” Al Iverson, industry research and community engagement lead at Valimail, told MarTech. “So you have requirements that are tightening up, meant to make it harder to send unwanted and unsolicited emails.”

How Big is the Spam Problem?

“The latest figure I saw was something like 347,000,000,000 emails sent a day,” Cynthia Price, SVP of Marketing at Litmus, told Martech. “And over half of those, depending on which metrics you look at, are estimated to be spam.”

That’s 173,000,000,000 spam emails a day. “The internet service providers, the Googles and the Yahoos and the Microsofts of the world are trying to do everything they can to hold down the fort and protect our inboxes from mayhem,” said Price.

The Cost of Email Deliverability Failure

According to Mailtrap, the cost of undelivered emails for U.S. businesses is:

$164+ million daily.
$1.1+ billion weekly.
$4.9+ billion monthly.
$59.5+ billion yearly.

Deliverability problems cost more than $15,000 for every million emails sent, according to a report by Validity. “A lot of people don’t understand they have deliverability problems until it’s too late,” said Price. “And, much like a credit score, it takes time to build it back up and to be recognized as a safe sender.”

13 Email Deliverability Issues and How to Solve Them

1. The Dreaded Spam Folder: Why Did My Emails Suddenly Land Here?

Your email marketing campaigns can dramatically drop in deliverability overnight, and one day, you are enjoying a healthy inbox placement rate when suddenly, your following email performance report reveals that most of your emails are going straight to the spam folder. What gives? Email marketing is often at a crossroads as unwanted emails battle for your attention. Not only do emails from spam senders make it to spam, but your business’s emails can also land in the spam.

That's when you have to circle back and see for gaps in infrastructure because that’s where the setup begins.

Infrastructure

IP reputation with Google & Microsoft can be measured by looking at Google Postmaster & SNDS. If your IP reputation has dipped, identify the root cause:

Identify which sender is responsible for the dip if it’s a shared IP.
If it's a dedicated IP, check what content and data were targeted on the day of the dip.

This is because your ESP needs to constantly monitor your IP so it doesn’t get listed, which we do at Mailmodo quite consistently. This helps maintain a good and consistent IP reputation.

End User Response

Avoid investing in third-party databases. Buying an email list may make your job easier, but in hindsight, that’s not the case because your emails reach recipients who share zero affinity with the brand.

As spam traps are not filtered, cleaning pre-bought databases with a tool will only do a little. Also, what happens to users who have uninstalled your app and share a reduced affinity with your brand? Thus, keeping a tab on the end-user response helps ensure deliverability.

Content Reputation

Deliverability issues related to content exist beyond the word FREE or other specific phrases. Let’s say your email campaign is on the receiving end of many spam complaints. As a result, the text in the footer can be a phone number, or your email ID gets cached negatively, causing it to land in spam even when you send it to the right audience segment from a different infrastructure.

The above is one of many instances that profoundly impact the content's reputation. Following best practices such as eliminating URL shorteners like /bit.ly and avoiding map tags, sometimes it’s better to prevent alt and title tags as they don’t impact emails in contrast to how they impact SEOs.

2. Do You Have Sudden Delivery Errors?

To determine delivery errors, you can use Google's Postmaster. The most common reasons include the following:

Temporary rate limits have been triggered because this domain or IP address has been sending traffic at an unusually high rate. The incoming traffic is suspected to be spam, and the incoming email could be spam due to problems with the content.
Attachments in emails that the ISP does not authorize. The DMARC policy of the sender’s domain doesn’t align with the recipient’s.
The sender’s domain and IP reputation are poor. Using Postmaster, you can identify the errors and how they significantly hamper your deliverability.

You can start by following these best practices:

Format emails as per Internet standards.
Don’t send messages without seeking consent, as there’s a possibility that the recipient will mark you spam in the future.
Build on increasing your sending volume slowly.
Verify the sending server’s PTR(pointer) record.

3. A Sudden Dip in Reputation? What Did I Do Wrong?

Let’s say most of your email list comprises gmails’s email addresses. So, by using Postmaster, we can analyze the root cause of the dip in reputation.

Because a dip in reputation is caused by various factors, including:

Have you stopped signing authentication?
Have you changed the content?
Are you experiencing high spam complaints because you have changed the target audience?
Adhering to authentication protocols shows email providers that you have taken all the steps to secure your email systems and demonstrates that you are indeed who you intend to be.

Improving Email Authentication and Security for Better Deliverability

From Postmaster’s dashboard you can gauge the number of emails that have passed the authentication checks through a graph. If there’s any discrepancy, you can see that your authentication sits at 0%. This is the call to fix your authentication problems.

Content is not just the copy but also the subject line, header, design, and use of qualified domain names instead of shortened links. Through unsecured HTTP websites, spammers introduce Trojans and worms and try to hijack websites, and you should switch to a more secure HTTP as it’s encrypted.

4. What Does It Mean If My IP Gets Blacklisted?

Suppose, let’s say, you've been working hard for weeks on crafting the perfect email, and now the results are showing. You're seeing an increase in deliverability rates. Upon reviewing the statistics in your email marketing platform, disappointment washes over you as you observe your deliverability rates plummeting.

This is because there’s an increased chance of your emails getting blacklisted. This can be classified into Real-time blacklists. Domain name server blacklists.

To find out whether you are on the blacklist, go to Mxtoolbox. It’s easy to check using the following steps:

Go to the official service page.
Enter your IP or domain address.
Press Check Blacklist.

Common reasons as to why your IP address is blacklisted can be due to various reasons:

At a minimum, emails have not been authenticated with DKIM & SPF. If you keep sending emails to inactive email addresses, even the best emails will end up in the spam folder sooner rather than later.
Sending volumes are high. Spammers send as many emails as they can, so you should monitor your sending volumes to avoid triggering blacklist suspicions.

Reconsider your sending frequency to prevent the issue. Some users will always complain about spam, and little can be done about it. If your spam complaint rate continues rising, you must find and fix the root cause.

5. Is My Email Sender Reputation So Bad That ISPs Are Blocking My Emails?

The ISPs take many factors into account, and if you are found sending spam emails, most ISPs will stop you from sending emails. In most cases, an ISP gets blocked because of a local policy on the recipient's email server or, in rare cases, because of a reputation issue with the IP address used to send the message. Also, they'll block you if you send email blasts without personalization while having a bad domain and IP reputation will let ISPs block your emails.

Preventing False Positives and Improving Email Deliverability with Proper Email Practices

For instance, if you have used Outlook, you must know that most legitimate emails are mistakenly blocked as threats(false positives).To avoid this, you can request recipients to mark your email as “not junk “and add you to their safe sender list. Also, security administrators enable end users to receive an email digest about quarantined messages.

The key to success in email marketing is discipline. Sending messages in a timely and consistent manner requires a well-planned email cadence. Following best practices and good email etiquette will help you improve your IP and domain reputation and keep your ISPs from blocking you.

6. Bounces Due To Authentication Errors Are No Good

Authentication-related bounces occur when the recipient's mailbox does not accept an email. It is commonly said that “your email bounced.” Bounces are of two types: hard and soft bounces. Authentication errors mainly cause them.

There are several reasons why authentication errors can cause bounces:

It is possible that the recipient's email address does not exist or needs to be corrected, resulting in a rejection.
With double-opt-in signups, you eliminate the possibility of receiving misspelled or nonexistent email addresses.
A soft bounce occurs when the recipient's mailbox is complete and the storage limit has been exceeded.
The email server will reject new messages until space is freed up. In such cases, the recipient must make room for new ones.
The email may be rejected if the sender’s domain is not authenticated. Some email servers require proper domain authentication (e.g., SPF, DKIM, DMARC).
The recipient's email server can block emails from specific sources using endpoint protection services, resulting in bounces. This can be addressed by enabling Branded URLs or authenticating the sending domain.

7. How Do I Check My IP Address Reputation?

If you’ve now tried all of the above steps and have still not identified why you’re going to the spam or junk folder, it’s likely that you’ve taken a hit to your sender reputation score and that blacklisting is now associated with your IP or domain. If the IP address that you’re sending emails from has been associated with spam in some way, it may be on one or more blacklists.

For example, AOL has its IP reputation monitor and rates the sender’s IP reputation as “bad,” “neutral,” and “good.” If your IP reputation is “bad” with AOL, your emails will be filtered out as junk mail or blocked altogether.

The Importance of IP Reputation in Email Deliverability and Spam Prevention

A “neutral” reputation is generally OK. Before checking the content of the email, the filters check the IP address to see if it is white- or blacklisted. If it is whitelisted, your email will be delivered without its content being checked. If the IP has been blacklisted, the email will be “blackholed,” bounced back, or flagged as spam without the content check.

Blackholed emails are not delivered to the user but are saved in a place accessible to administrators in case they are needed later. This approach is often used for emails containing viruses to keep end-users from accidentally opening them.

Testing the IP Address Reputation

You can do a couple of things to test your IP reputation:

1. Send your email through a different mail server or service provider.

For example, if you regularly send emails through your mail server, consider sending them through an email service provider or delivery services such as Amazon SES, SparkPost, Mailgun, or others.

Keep the same subject, sending address, and content. If the email was blocked when sent through your server but is delivered with no problems through an ESP or delivery service, you may have an IP reputation problem.

2. Test your IP against blacklists with the GlockApps IP blacklist checker.

You can set up an automated process of checking your IP against blacklists and be alerted via email, Slack, or Telegram when the IP gets blacklisted. IP reputation monitor checks all major blacklists in the industry and alarms if the IP gets blacklisted.

Suppose the email isn’t delivered using a different server or service provider. In that case, you may have a problem with one of the things listed above, like the sender’s email address/domain reputation or content.

3. Correcting IP Address Reputation Problems.

If you have a blacklisting issue, go through the removal process. The removal instructions are usually stated on the blacklist’s website. It makes sense only if you are sending via your mail server and have control over your sending IP. If you are sending emails via an email service provider or SMTP relay service, they usually use several IPs and de-list blacklisted IPs themselves periodically.

You can also reduce the size of your email list to only send to the most engaged users. Remove anybody who doesn’t regularly open and respond to emails from your list. Then, I send it to only my most active subscribers. This will improve my email metrics with email service providers because it will demonstrate high open rates and low unsubscribe or spam complaints. A smaller number of emails also means a higher chance of getting into the Inbox. It’s not an ideal fix, but it allows you to continue sending regularly with limited results.

4. What if IP Reputation is Beyond Fixing?

This is a miserable and challenging situation. If your IP reputation is killed and nothing helps, you’ll need to acquire a new IP to send from. It may not solve all your deliverability issues because spam filters can associate your reputation with your IP address, domain, or both.

Thus, changing both the IP address (probably by changing ESPs) and the domain would be the best solution, but it is not possible for most companies, as the domain cannot be abandoned. In this case, change the IP, register a new sub-domain using your brand, for example, mail.brand.com, set up a new sending address and authentication records, and begin using best practices to achieve good engagement and reputation.

8. Are You Settling for a Single Opt-in?

Confirmed (or double) opt-in means that, after people select to sign up for your email list, they receive a confirmation email they must use to verify their subscription. Confirmations are great options for a double opt-in.

Not only does a confirmed opt-in help protect you from erroneous signups and spambots, but confirmed opt-in lists see better results with almost every engagement metric, other than the sheer number of sign-ups compared to single opt-in lists. Confirmed opt-in lists are more engaged from the start, and by using confirmed opt-in, you can more effectively build your sending reputation by sending to a more involved and active list.

9. Unclear or Spam-Flagging Subject Lines Are Bad for Deliverability

Your subject line is the welcome mat of your email and, often, issues with subject lines are as simple as this: If your subject line makes your email look like spam, then people and the spam filters ISPs put in place to protect them will probably think that it’s spam.

Avoid ALL CAPITALS, excessive and unnecessary punctuation (!!!), and use symbols and SP$C!AL CH@RCT3RZ sparingly and only when relevant. Also, ensure that your subject lines match the content of your email. No one wants to be promised a trip to a theme park and be at the dentist. An “RE” or “FWD” prefix is misleading when there’s been no such previous contact or email exchange.

Crafting Effective Subject Lines for Better Email Open Rates

Does your email require “urgent action,” and is my offer “exclusive” and “one time only” designations? If not, leave them out. Best practices for the rest of your email copy are also valid for your subject lines.

Be concise, as many email clients may need to correct subject lines with more characters. Use personalization, be creative with your copy, and be transparent with your subscribers about what the email contains.

10. Designing Emails with Too Many Images Is Not Ideal

A historic spam technique was sending emails containing just one image or many images and very little text in HTML emails to bypass spam filters based primarily on spam keywords. Spam filtering is now based much more on sending reputation than content, though the image-to-text ratio still carries some weight with spam filters and is something you’ll want to spend time getting right.

Balancing Images and Text for Effective Email Design

Emails with very little copy and many images, or simply composed of one large image, can be hallmarks of spammers. By composing similar emails, you can risk your email being flagged as spam. Remember, many email clients or devices aren’t configured to display images by default. Suppose your email is composed almost entirely of images a recipient’s email client doesn’t display.

In that case, the content of your email will be unreadable and certainly not something your client can interact with easily. Too many images can look spammy. Instead, design your emails with this in mind and ensure we balance your images and copy so that your email makes sense and engages even if the images are not displayed. I always use alt text for my pictures, so even if they don’t render, your subscribers will have some context for what the photos are.

11. Using URL Shorteners Can Kill Your Deliverability

The use of URL shorteners is a notorious technique used by spammers to hide the nature of URLs they link to and, as such, rank high on reasons spam filters can block your emails, even if the links themselves are legitimate. Avoid using URL shorteners and inserting the full URL link as text in the body of your email.

Instead, create a hyperlink with the appropriate text and ensure all my links go to legitimate domains and are valid and functional. Replacing URL shorteners with clear and attractive CTAs will drive traffic and see more click-throughs on your sends. This is another piece of the sending reputation pie that can further boost your email deliverability.

12. Are You Making It Difficult to Unsubscribe?

While an unsubscribe link must be included in every email sent through Campaign Monitor, we also recommend that it be simple and easy for your recipients to find. Hiding your unsubscribe link in a wall of text with an 8pt font will only frustrate your recipients should they attempt to unsubscribe. In our experience, the more difficult it is to unsubscribe, the more likely your recipients will mark your email as spam.

The Importance of Clear and Accessible Unsubscribe Options

Roku does an excellent job of making its unsubscribe link easy to find. Instead of including it in a large wall of text, it is set apart from the other information so users can see it and click it to remove themselves from the list.

Make your unsubscribe option clear and easily visible, and, better yet, add a permission reminder message to remind people where they signed up or permitted you and point them to unsubscribing if they’re no longer interested in receiving your emails. Your recipients will appreciate this honesty and clarity, and an unengaged recipient choosing to unsubscribe is always preferable to receiving a spam complaint.

13. What Are Spam Traps and Why Are They Bad?

The other reason for being put into spam folders is if you send to spam traps. There are two types of spam traps:

Recycled Email Addresses

Recycled spam traps are email addresses that once belonged to an actual person but have been abandoned for a while. ISPs turn these mailboxes into spam traps, meaning that the mailbox still exists (so you will not see any bounces) but belongs to the ISP rather than a person. These traps catch senders that need to use industry best practices, such as keeping a healthy database by regularly removing bounced or non-engaged contacts.

Artificial Email Addresses

ISPs and spam blocklist providers also create fake email accounts that have never belonged to anyone (and have, therefore, never subscribed to any marketing mailing). These traps are meant to catch senders that buy address lists.

Multiple reasons for hitting spam traps exist:

Your data capture points need to be carefully set up; for example, you do not use double opt-in (DOI).
You try to send to a contact base that is old or has yet to be verified in the last year.
You need to clean up your database of bounces and inactive contacts frequently.
You revalidate bounced email addresses now and then without understanding the bounce reasons.
You buy address lists.

5 Best Practices to Improve Email Deliverability

1. Create Good Quality Content for Improved Email Deliverability

Engagement matters in email marketing. When emails sit unopened in inboxes, it signals to ISPs that you’re sending emails recipients don’t want. This hurts your sender’s reputation and email deliverability.

To improve engagement, test your email to ensure it renders as expected. You can use the test in email client features to ensure your email is optimized for mobile devices. Within the email editor, click the bar graph icon to open the email optimizer and review recommendations to improve your email content and deliverability.

2. Use Email Features that Improve Deliverability

Work with your IT team to connect your email-sending domain. Adding a few records to your Domain Name Server (i.e., GoDaddy) confirms that you own the email domain you're using with HubSpot. This makes your emails look more authentic to email filters. If your IT team uses a DMARC policy, update all necessary records. Turn on double opt-in on your HubSpot forms. When this feature is enabled, contacts who submit a form will receive a follow-up email with a link to confirm their subscription.

Enhancing Deliverability with Graymail Suppression

This extra step helps you avoid fake or misspelled email addresses and ensures that all new contacts added to your database actively engage with your content. Turn on graymail suppression in your email settings. Graymail is a term for email that sits unopened in your recipients' inbox, which makes you look like a sender who's sending spam.

This feature uses the Sends since last engagement contact property to automatically exclude contacts not engaging with your emails to improve your email deliverability results instantly.

3. Warm Up Your Email Sending

To ensure consistent delivery and establish a positive reputation with email inbox providers, you should gradually ramp up the volume and frequency of the emails you send. You’ll go through an automated 40-day warm-up period when you purchase the dedicated IP add-on. Your email traffic will be split between HubSpot's shared network and your new IP address. If you opt out of this automated warm-up period, you should manually increase your email volume.

Learn more about IP warm-up here. If you recently migrated to a brand new domain or email service provider, mailbox providers, and ISPs will immediately not recognize the new domain when email is delivered. You should send a few emails first, then gradually increase your email volume over 30 to 60 days. Regularly monitor your sending reputation for continued favorable engagement rates, such as your cumulative click and open rates. Using the Email Health tool, you can check your deliverability performance over the last 30 days.

4. Analyze Email Performance

Use insights from your past email campaigns to improve engagement over time. Review your contact lists regularly to identify outdated email addresses and unengaged contacts. Remove these contacts from your lists to see better email metrics and boost your sending reputation. Email engagements are stored in a series of contact properties that help you identify trends and take action to improve your future email results.

Using A/B Testing to Optimize Email Campaigns

Learn to analyze your email results. Email opens and clicks demonstrate that you're sending your subscribers the right types of content. Spam complaints, high bounce rates, and unsubscribes are hostile email engagements that can damage your email-sending reputation.

Track your results to learn what content resonates with your readers and which contacts you should include in your email campaigns. By varying the send time, subject line, or content of your email, you can run an A/B test on your marketing emails.

5. Perfect Your Opt-In Process

Implementing an opt-in process where subscribers confirm their email addresses after signing up is very important. This helps ensure that the email addresses provided are valid and that your email list of engaged users is complete.

Start Buying Domains Now and Setup Your Email Infrastructure Today

Inframail is revolutionizing cold email deliverability. This platform offers unlimited inboxes at a flat rate, unlike traditional providers, charging per inbox.

With Inframail, users can avoid costly email deliverability issues from using too many inboxes to reach their goals and getting flagged by spam filters.

What Is Email Deliverability?

Email deliverability is a critical metric that measures how many emails land in the end user's inbox. While email delivery measures how many emails got delivered, deliverability measures how many ended up in the inbox. The average deliverability is 84.2%.

Why is Email Deliverability Important?

Deliverability is critical when it comes to email outreach. Akin to how a runner undergoes checks to ensure fair competition, your email goes through spam filter checks, from authentication to the spam score of templates. Similarly, emails with proper authentication and favorable sender reputations are more likely to pass the spam filter successfully, improving their chances of landing inbox placement.

Obstacles such as incorrect addresses or content issues can delay or disqualify your email (going to spam or bouncing). The goal of every marketer is to see his email make it to the recipient’s inbox. Maintaining a reasonable deliverability rate ensures that The emails you send don’t get lost in the spam folder. You keep a good reputation with the ISPs. You achieve the ultimate goal—conversion.

Why Are Email Deliverability Rules Getting Tougher?

“Google, Yahoo, and many other mailbox providers are getting increasingly frustrated with having to deal with spam,” Al Iverson, industry research and community engagement lead at Valimail, told MarTech. “So you have requirements that are tightening up, meant to make it harder to send unwanted and unsolicited emails.”

How Big is the Spam Problem?

“The latest figure I saw was something like 347,000,000,000 emails sent a day,” Cynthia Price, SVP of Marketing at Litmus, told Martech. “And over half of those, depending on which metrics you look at, are estimated to be spam.”

That’s 173,000,000,000 spam emails a day. “The internet service providers, the Googles and the Yahoos and the Microsofts of the world are trying to do everything they can to hold down the fort and protect our inboxes from mayhem,” said Price.

The Cost of Email Deliverability Failure

According to Mailtrap, the cost of undelivered emails for U.S. businesses is:

$164+ million daily.
$1.1+ billion weekly.
$4.9+ billion monthly.
$59.5+ billion yearly.

Deliverability problems cost more than $15,000 for every million emails sent, according to a report by Validity. “A lot of people don’t understand they have deliverability problems until it’s too late,” said Price. “And, much like a credit score, it takes time to build it back up and to be recognized as a safe sender.”

13 Email Deliverability Issues and How to Solve Them

1. The Dreaded Spam Folder: Why Did My Emails Suddenly Land Here?

Your email marketing campaigns can dramatically drop in deliverability overnight, and one day, you are enjoying a healthy inbox placement rate when suddenly, your following email performance report reveals that most of your emails are going straight to the spam folder. What gives? Email marketing is often at a crossroads as unwanted emails battle for your attention. Not only do emails from spam senders make it to spam, but your business’s emails can also land in the spam.

That's when you have to circle back and see for gaps in infrastructure because that’s where the setup begins.

Infrastructure

IP reputation with Google & Microsoft can be measured by looking at Google Postmaster & SNDS. If your IP reputation has dipped, identify the root cause:

Identify which sender is responsible for the dip if it’s a shared IP.
If it's a dedicated IP, check what content and data were targeted on the day of the dip.

This is because your ESP needs to constantly monitor your IP so it doesn’t get listed, which we do at Mailmodo quite consistently. This helps maintain a good and consistent IP reputation.

End User Response

Avoid investing in third-party databases. Buying an email list may make your job easier, but in hindsight, that’s not the case because your emails reach recipients who share zero affinity with the brand.

As spam traps are not filtered, cleaning pre-bought databases with a tool will only do a little. Also, what happens to users who have uninstalled your app and share a reduced affinity with your brand? Thus, keeping a tab on the end-user response helps ensure deliverability.

Content Reputation

Deliverability issues related to content exist beyond the word FREE or other specific phrases. Let’s say your email campaign is on the receiving end of many spam complaints. As a result, the text in the footer can be a phone number, or your email ID gets cached negatively, causing it to land in spam even when you send it to the right audience segment from a different infrastructure.

The above is one of many instances that profoundly impact the content's reputation. Following best practices such as eliminating URL shorteners like /bit.ly and avoiding map tags, sometimes it’s better to prevent alt and title tags as they don’t impact emails in contrast to how they impact SEOs.

2. Do You Have Sudden Delivery Errors?

To determine delivery errors, you can use Google's Postmaster. The most common reasons include the following:

Temporary rate limits have been triggered because this domain or IP address has been sending traffic at an unusually high rate. The incoming traffic is suspected to be spam, and the incoming email could be spam due to problems with the content.
Attachments in emails that the ISP does not authorize. The DMARC policy of the sender’s domain doesn’t align with the recipient’s.
The sender’s domain and IP reputation are poor. Using Postmaster, you can identify the errors and how they significantly hamper your deliverability.

You can start by following these best practices:

Format emails as per Internet standards.
Don’t send messages without seeking consent, as there’s a possibility that the recipient will mark you spam in the future.
Build on increasing your sending volume slowly.
Verify the sending server’s PTR(pointer) record.

3. A Sudden Dip in Reputation? What Did I Do Wrong?

Let’s say most of your email list comprises gmails’s email addresses. So, by using Postmaster, we can analyze the root cause of the dip in reputation.

Because a dip in reputation is caused by various factors, including:

Have you stopped signing authentication?
Have you changed the content?
Are you experiencing high spam complaints because you have changed the target audience?
Adhering to authentication protocols shows email providers that you have taken all the steps to secure your email systems and demonstrates that you are indeed who you intend to be.

Improving Email Authentication and Security for Better Deliverability

From Postmaster’s dashboard you can gauge the number of emails that have passed the authentication checks through a graph. If there’s any discrepancy, you can see that your authentication sits at 0%. This is the call to fix your authentication problems.

Content is not just the copy but also the subject line, header, design, and use of qualified domain names instead of shortened links. Through unsecured HTTP websites, spammers introduce Trojans and worms and try to hijack websites, and you should switch to a more secure HTTP as it’s encrypted.

4. What Does It Mean If My IP Gets Blacklisted?

Suppose, let’s say, you've been working hard for weeks on crafting the perfect email, and now the results are showing. You're seeing an increase in deliverability rates. Upon reviewing the statistics in your email marketing platform, disappointment washes over you as you observe your deliverability rates plummeting.

This is because there’s an increased chance of your emails getting blacklisted. This can be classified into Real-time blacklists. Domain name server blacklists.

To find out whether you are on the blacklist, go to Mxtoolbox. It’s easy to check using the following steps:

Go to the official service page.
Enter your IP or domain address.
Press Check Blacklist.

Common reasons as to why your IP address is blacklisted can be due to various reasons:

At a minimum, emails have not been authenticated with DKIM & SPF. If you keep sending emails to inactive email addresses, even the best emails will end up in the spam folder sooner rather than later.
Sending volumes are high. Spammers send as many emails as they can, so you should monitor your sending volumes to avoid triggering blacklist suspicions.

Reconsider your sending frequency to prevent the issue. Some users will always complain about spam, and little can be done about it. If your spam complaint rate continues rising, you must find and fix the root cause.

5. Is My Email Sender Reputation So Bad That ISPs Are Blocking My Emails?

The ISPs take many factors into account, and if you are found sending spam emails, most ISPs will stop you from sending emails. In most cases, an ISP gets blocked because of a local policy on the recipient's email server or, in rare cases, because of a reputation issue with the IP address used to send the message. Also, they'll block you if you send email blasts without personalization while having a bad domain and IP reputation will let ISPs block your emails.

Preventing False Positives and Improving Email Deliverability with Proper Email Practices

For instance, if you have used Outlook, you must know that most legitimate emails are mistakenly blocked as threats(false positives).To avoid this, you can request recipients to mark your email as “not junk “and add you to their safe sender list. Also, security administrators enable end users to receive an email digest about quarantined messages.

The key to success in email marketing is discipline. Sending messages in a timely and consistent manner requires a well-planned email cadence. Following best practices and good email etiquette will help you improve your IP and domain reputation and keep your ISPs from blocking you.

6. Bounces Due To Authentication Errors Are No Good

Authentication-related bounces occur when the recipient's mailbox does not accept an email. It is commonly said that “your email bounced.” Bounces are of two types: hard and soft bounces. Authentication errors mainly cause them.

There are several reasons why authentication errors can cause bounces:

It is possible that the recipient's email address does not exist or needs to be corrected, resulting in a rejection.
With double-opt-in signups, you eliminate the possibility of receiving misspelled or nonexistent email addresses.
A soft bounce occurs when the recipient's mailbox is complete and the storage limit has been exceeded.
The email server will reject new messages until space is freed up. In such cases, the recipient must make room for new ones.
The email may be rejected if the sender’s domain is not authenticated. Some email servers require proper domain authentication (e.g., SPF, DKIM, DMARC).
The recipient's email server can block emails from specific sources using endpoint protection services, resulting in bounces. This can be addressed by enabling Branded URLs or authenticating the sending domain.

7. How Do I Check My IP Address Reputation?

If you’ve now tried all of the above steps and have still not identified why you’re going to the spam or junk folder, it’s likely that you’ve taken a hit to your sender reputation score and that blacklisting is now associated with your IP or domain. If the IP address that you’re sending emails from has been associated with spam in some way, it may be on one or more blacklists.

For example, AOL has its IP reputation monitor and rates the sender’s IP reputation as “bad,” “neutral,” and “good.” If your IP reputation is “bad” with AOL, your emails will be filtered out as junk mail or blocked altogether.

The Importance of IP Reputation in Email Deliverability and Spam Prevention

A “neutral” reputation is generally OK. Before checking the content of the email, the filters check the IP address to see if it is white- or blacklisted. If it is whitelisted, your email will be delivered without its content being checked. If the IP has been blacklisted, the email will be “blackholed,” bounced back, or flagged as spam without the content check.

Blackholed emails are not delivered to the user but are saved in a place accessible to administrators in case they are needed later. This approach is often used for emails containing viruses to keep end-users from accidentally opening them.

Testing the IP Address Reputation

You can do a couple of things to test your IP reputation:

1. Send your email through a different mail server or service provider.

For example, if you regularly send emails through your mail server, consider sending them through an email service provider or delivery services such as Amazon SES, SparkPost, Mailgun, or others.

Keep the same subject, sending address, and content. If the email was blocked when sent through your server but is delivered with no problems through an ESP or delivery service, you may have an IP reputation problem.

2. Test your IP against blacklists with the GlockApps IP blacklist checker.

You can set up an automated process of checking your IP against blacklists and be alerted via email, Slack, or Telegram when the IP gets blacklisted. IP reputation monitor checks all major blacklists in the industry and alarms if the IP gets blacklisted.

Suppose the email isn’t delivered using a different server or service provider. In that case, you may have a problem with one of the things listed above, like the sender’s email address/domain reputation or content.

3. Correcting IP Address Reputation Problems.

If you have a blacklisting issue, go through the removal process. The removal instructions are usually stated on the blacklist’s website. It makes sense only if you are sending via your mail server and have control over your sending IP. If you are sending emails via an email service provider or SMTP relay service, they usually use several IPs and de-list blacklisted IPs themselves periodically.

You can also reduce the size of your email list to only send to the most engaged users. Remove anybody who doesn’t regularly open and respond to emails from your list. Then, I send it to only my most active subscribers. This will improve my email metrics with email service providers because it will demonstrate high open rates and low unsubscribe or spam complaints. A smaller number of emails also means a higher chance of getting into the Inbox. It’s not an ideal fix, but it allows you to continue sending regularly with limited results.

4. What if IP Reputation is Beyond Fixing?

This is a miserable and challenging situation. If your IP reputation is killed and nothing helps, you’ll need to acquire a new IP to send from. It may not solve all your deliverability issues because spam filters can associate your reputation with your IP address, domain, or both.

Thus, changing both the IP address (probably by changing ESPs) and the domain would be the best solution, but it is not possible for most companies, as the domain cannot be abandoned. In this case, change the IP, register a new sub-domain using your brand, for example, mail.brand.com, set up a new sending address and authentication records, and begin using best practices to achieve good engagement and reputation.

8. Are You Settling for a Single Opt-in?

Confirmed (or double) opt-in means that, after people select to sign up for your email list, they receive a confirmation email they must use to verify their subscription. Confirmations are great options for a double opt-in.

Not only does a confirmed opt-in help protect you from erroneous signups and spambots, but confirmed opt-in lists see better results with almost every engagement metric, other than the sheer number of sign-ups compared to single opt-in lists. Confirmed opt-in lists are more engaged from the start, and by using confirmed opt-in, you can more effectively build your sending reputation by sending to a more involved and active list.

9. Unclear or Spam-Flagging Subject Lines Are Bad for Deliverability

Your subject line is the welcome mat of your email and, often, issues with subject lines are as simple as this: If your subject line makes your email look like spam, then people and the spam filters ISPs put in place to protect them will probably think that it’s spam.

Avoid ALL CAPITALS, excessive and unnecessary punctuation (!!!), and use symbols and SP$C!AL CH@RCT3RZ sparingly and only when relevant. Also, ensure that your subject lines match the content of your email. No one wants to be promised a trip to a theme park and be at the dentist. An “RE” or “FWD” prefix is misleading when there’s been no such previous contact or email exchange.

Crafting Effective Subject Lines for Better Email Open Rates

Does your email require “urgent action,” and is my offer “exclusive” and “one time only” designations? If not, leave them out. Best practices for the rest of your email copy are also valid for your subject lines.

Be concise, as many email clients may need to correct subject lines with more characters. Use personalization, be creative with your copy, and be transparent with your subscribers about what the email contains.

10. Designing Emails with Too Many Images Is Not Ideal

A historic spam technique was sending emails containing just one image or many images and very little text in HTML emails to bypass spam filters based primarily on spam keywords. Spam filtering is now based much more on sending reputation than content, though the image-to-text ratio still carries some weight with spam filters and is something you’ll want to spend time getting right.

Balancing Images and Text for Effective Email Design

Emails with very little copy and many images, or simply composed of one large image, can be hallmarks of spammers. By composing similar emails, you can risk your email being flagged as spam. Remember, many email clients or devices aren’t configured to display images by default. Suppose your email is composed almost entirely of images a recipient’s email client doesn’t display.

In that case, the content of your email will be unreadable and certainly not something your client can interact with easily. Too many images can look spammy. Instead, design your emails with this in mind and ensure we balance your images and copy so that your email makes sense and engages even if the images are not displayed. I always use alt text for my pictures, so even if they don’t render, your subscribers will have some context for what the photos are.

11. Using URL Shorteners Can Kill Your Deliverability

The use of URL shorteners is a notorious technique used by spammers to hide the nature of URLs they link to and, as such, rank high on reasons spam filters can block your emails, even if the links themselves are legitimate. Avoid using URL shorteners and inserting the full URL link as text in the body of your email.

Instead, create a hyperlink with the appropriate text and ensure all my links go to legitimate domains and are valid and functional. Replacing URL shorteners with clear and attractive CTAs will drive traffic and see more click-throughs on your sends. This is another piece of the sending reputation pie that can further boost your email deliverability.

12. Are You Making It Difficult to Unsubscribe?

While an unsubscribe link must be included in every email sent through Campaign Monitor, we also recommend that it be simple and easy for your recipients to find. Hiding your unsubscribe link in a wall of text with an 8pt font will only frustrate your recipients should they attempt to unsubscribe. In our experience, the more difficult it is to unsubscribe, the more likely your recipients will mark your email as spam.

The Importance of Clear and Accessible Unsubscribe Options

Roku does an excellent job of making its unsubscribe link easy to find. Instead of including it in a large wall of text, it is set apart from the other information so users can see it and click it to remove themselves from the list.

Make your unsubscribe option clear and easily visible, and, better yet, add a permission reminder message to remind people where they signed up or permitted you and point them to unsubscribing if they’re no longer interested in receiving your emails. Your recipients will appreciate this honesty and clarity, and an unengaged recipient choosing to unsubscribe is always preferable to receiving a spam complaint.

13. What Are Spam Traps and Why Are They Bad?

The other reason for being put into spam folders is if you send to spam traps. There are two types of spam traps:

Recycled Email Addresses

Recycled spam traps are email addresses that once belonged to an actual person but have been abandoned for a while. ISPs turn these mailboxes into spam traps, meaning that the mailbox still exists (so you will not see any bounces) but belongs to the ISP rather than a person. These traps catch senders that need to use industry best practices, such as keeping a healthy database by regularly removing bounced or non-engaged contacts.

Artificial Email Addresses

ISPs and spam blocklist providers also create fake email accounts that have never belonged to anyone (and have, therefore, never subscribed to any marketing mailing). These traps are meant to catch senders that buy address lists.

Multiple reasons for hitting spam traps exist:

Your data capture points need to be carefully set up; for example, you do not use double opt-in (DOI).
You try to send to a contact base that is old or has yet to be verified in the last year.
You need to clean up your database of bounces and inactive contacts frequently.
You revalidate bounced email addresses now and then without understanding the bounce reasons.
You buy address lists.

5 Best Practices to Improve Email Deliverability

1. Create Good Quality Content for Improved Email Deliverability

Engagement matters in email marketing. When emails sit unopened in inboxes, it signals to ISPs that you’re sending emails recipients don’t want. This hurts your sender’s reputation and email deliverability.

To improve engagement, test your email to ensure it renders as expected. You can use the test in email client features to ensure your email is optimized for mobile devices. Within the email editor, click the bar graph icon to open the email optimizer and review recommendations to improve your email content and deliverability.

2. Use Email Features that Improve Deliverability

Work with your IT team to connect your email-sending domain. Adding a few records to your Domain Name Server (i.e., GoDaddy) confirms that you own the email domain you're using with HubSpot. This makes your emails look more authentic to email filters. If your IT team uses a DMARC policy, update all necessary records. Turn on double opt-in on your HubSpot forms. When this feature is enabled, contacts who submit a form will receive a follow-up email with a link to confirm their subscription.

Enhancing Deliverability with Graymail Suppression

This extra step helps you avoid fake or misspelled email addresses and ensures that all new contacts added to your database actively engage with your content. Turn on graymail suppression in your email settings. Graymail is a term for email that sits unopened in your recipients' inbox, which makes you look like a sender who's sending spam.

This feature uses the Sends since last engagement contact property to automatically exclude contacts not engaging with your emails to improve your email deliverability results instantly.

3. Warm Up Your Email Sending

To ensure consistent delivery and establish a positive reputation with email inbox providers, you should gradually ramp up the volume and frequency of the emails you send. You’ll go through an automated 40-day warm-up period when you purchase the dedicated IP add-on. Your email traffic will be split between HubSpot's shared network and your new IP address. If you opt out of this automated warm-up period, you should manually increase your email volume.

Learn more about IP warm-up here. If you recently migrated to a brand new domain or email service provider, mailbox providers, and ISPs will immediately not recognize the new domain when email is delivered. You should send a few emails first, then gradually increase your email volume over 30 to 60 days. Regularly monitor your sending reputation for continued favorable engagement rates, such as your cumulative click and open rates. Using the Email Health tool, you can check your deliverability performance over the last 30 days.

4. Analyze Email Performance

Use insights from your past email campaigns to improve engagement over time. Review your contact lists regularly to identify outdated email addresses and unengaged contacts. Remove these contacts from your lists to see better email metrics and boost your sending reputation. Email engagements are stored in a series of contact properties that help you identify trends and take action to improve your future email results.

Using A/B Testing to Optimize Email Campaigns

Learn to analyze your email results. Email opens and clicks demonstrate that you're sending your subscribers the right types of content. Spam complaints, high bounce rates, and unsubscribes are hostile email engagements that can damage your email-sending reputation.

Track your results to learn what content resonates with your readers and which contacts you should include in your email campaigns. By varying the send time, subject line, or content of your email, you can run an A/B test on your marketing emails.

5. Perfect Your Opt-In Process

Implementing an opt-in process where subscribers confirm their email addresses after signing up is very important. This helps ensure that the email addresses provided are valid and that your email list of engaged users is complete.

Start Buying Domains Now and Setup Your Email Infrastructure Today

Inframail is revolutionizing cold email deliverability. This platform offers unlimited inboxes at a flat rate, unlike traditional providers, charging per inbox.

With Inframail, users can avoid costly email deliverability issues from using too many inboxes to reach their goals and getting flagged by spam filters.

Top 13 Email Deliverability Issues & 5 Tips to Fix Them Fast

Top 13 Email Deliverability Issues & 5 Tips to Fix Them Fast

Top 13 Email Deliverability Issues & 5 Tips to Fix Them Fast

Table of Contents

What Is Email Deliverability?

Why is Email Deliverability Important?

Why Are Email Deliverability Rules Getting Tougher?

How Big is the Spam Problem?

The Cost of Email Deliverability Failure

Related Reading

13 Email Deliverability Issues and How to Solve Them

1. The Dreaded Spam Folder: Why Did My Emails Suddenly Land Here?

Infrastructure

End User Response

Content Reputation

2. Do You Have Sudden Delivery Errors?

3. A Sudden Dip in Reputation? What Did I Do Wrong?

Improving Email Authentication and Security for Better Deliverability

4. What Does It Mean If My IP Gets Blacklisted?

5. Is My Email Sender Reputation So Bad That ISPs Are Blocking My Emails?

Preventing False Positives and Improving Email Deliverability with Proper Email Practices

6. Bounces Due To Authentication Errors Are No Good

7. How Do I Check My IP Address Reputation?

The Importance of IP Reputation in Email Deliverability and Spam Prevention

Testing the IP Address Reputation

1. Send your email through a different mail server or service provider.

2. Test your IP against blacklists with the GlockApps IP blacklist checker.

3. Correcting IP Address Reputation Problems.

4. What if IP Reputation is Beyond Fixing?

8. Are You Settling for a Single Opt-in?

9. Unclear or Spam-Flagging Subject Lines Are Bad for Deliverability

Crafting Effective Subject Lines for Better Email Open Rates

10. Designing Emails with Too Many Images Is Not Ideal

Balancing Images and Text for Effective Email Design

11. Using URL Shorteners Can Kill Your Deliverability

12. Are You Making It Difficult to Unsubscribe?

The Importance of Clear and Accessible Unsubscribe Options

13. What Are Spam Traps and Why Are They Bad?

Recycled Email Addresses

Artificial Email Addresses

Related Reading

5 Best Practices to Improve Email Deliverability

1. Create Good Quality Content for Improved Email Deliverability

2. Use Email Features that Improve Deliverability

Enhancing Deliverability with Graymail Suppression

3. Warm Up Your Email Sending

4. Analyze Email Performance

Using A/B Testing to Optimize Email Campaigns

5. Perfect Your Opt-In Process

Start Buying Domains Now and Setup Your Email Infrastructure Today

Related Reading

Table of Contents

What Is Email Deliverability?

Why is Email Deliverability Important?

Why Are Email Deliverability Rules Getting Tougher?

How Big is the Spam Problem?

The Cost of Email Deliverability Failure

Related Reading

13 Email Deliverability Issues and How to Solve Them

1. The Dreaded Spam Folder: Why Did My Emails Suddenly Land Here?

Infrastructure

End User Response

Content Reputation

2. Do You Have Sudden Delivery Errors?

3. A Sudden Dip in Reputation? What Did I Do Wrong?

Improving Email Authentication and Security for Better Deliverability

4. What Does It Mean If My IP Gets Blacklisted?

5. Is My Email Sender Reputation So Bad That ISPs Are Blocking My Emails?

Preventing False Positives and Improving Email Deliverability with Proper Email Practices

6. Bounces Due To Authentication Errors Are No Good

7. How Do I Check My IP Address Reputation?

The Importance of IP Reputation in Email Deliverability and Spam Prevention

Testing the IP Address Reputation

1. Send your email through a different mail server or service provider.

2. Test your IP against blacklists with the GlockApps IP blacklist checker.

3. Correcting IP Address Reputation Problems.

4. What if IP Reputation is Beyond Fixing?

8. Are You Settling for a Single Opt-in?

9. Unclear or Spam-Flagging Subject Lines Are Bad for Deliverability

Crafting Effective Subject Lines for Better Email Open Rates