Email Bounce and Its Prevention: Tips on Reducing Email Bounce Rate

Email Bounce and Its Prevention: Tips on Reducing Email Bounce Rate
12 May, 2022 • ... • 1035 views
Irene Dmitrieva
by Irene Dmitrieva

As an email marketer, it is your job to make sure that people open and click on the emails that you send out. To be successful, you have to constantly experiment to find what works and what doesn’t. But there’s always the risk that your email will bounce back and never reach the person you’re sending it to.

This guide is about why bounced emails happen and what you can do to prevent them. We will also provide tips on how to reduce high email bounce-back rates and optimize email outreach and email marketing efforts.

What is an email bounce?

When a message cannot be delivered, it is returned to the sender with an error message that explains why the delivery failed. This is called a bounce back.

The email bounce rate is a measure of the percentage of emails that are returned to the sender due to being undeliverable. To calculate this metric, simply divide the number of emails that could not be delivered by the total number of emails sent, and multiply by 100. For example, if you send 1000 emails and 100 of them are unable to be delivered, your email bounce rate would be 10%.

A few bounced emails are something that happens to everyone. So what can be considered a “good” bounce rate? The average email bounce rate varies across different industries. To achieve the best results, this rate should be kept below 2%, as a low email bounce rate indicates that more of your emails are reaching the intended recipients.

The table shows data about email bounce rates for different industries worldwide:

Average email bounce data
Source: Campaign Monitor

Email bounces can have a variety of negative effects on your domain and IP address. They decrease your email sender score and email marketing deliverability rate. If you have a high bounce rate, it may indicate to email servers that your emails are not trustworthy, and they may start blocking them automatically.

How to identify a bounced email

Here is an example of a bounce-back message:

Bounced-back email

The image above shows the bounced email from the mail service. In our case, the main reason for the bounce back is the non-existence of an email address. Some of the major service providers such as Gmail provide recommendations on how to fix this issue.

The Selzy email marketing platform provides a report detailing undelivered messages, as well as the reason for each bounced email address:

Undelivered messages report in Selzy

Types of email bounces

There are soft bounces, hard bounces, and blacklisted emails. Each type of bounce category requires a different approach to resolve the issue and ensure that your emails continue to be delivered successfully.

Hard bounces

A hard bounce occurs when an email cannot be delivered to the recipient. This can happen if the recipient’s address is incorrect or invalid, or if the recipient’s server blocks emails from the sender’s domain. Hard bounces can also occur if there are inappropriate links or spam content in the email. If you get a lot of hard bounces it can result in your emails being blacklisted. To avoid this, it’s best to remove any bounced addresses from your mailing list.

Soft bounces

A soft bounce occurs when an email is rejected by a server due to temporary issues, such as a full mailbox or technical problems with the server. There are other possible causes of a soft bounce, including high email volume, large attachments or images, server downtime, and vacation autoresponders. These issues are temporary, they will eventually be fixed.

Blacklisted emails

An email blacklist is a database of IP addresses and email domains that have been flagged as sources of spam.

Email services like Gmail use spam lists to prevent spam messages from reaching their customers’ inboxes. If you are not getting enough website traffic, it’s possible that your domain or IP address has been blacklisted for having high bounce rates or low delivery rates. To see if you’re on a blacklist, you can search popular blacklist holders such as Spamhaus, Spamcop, and SORbS to check your email server IP and domain reputation score through online tools such as Mxtoolbox or SenderScore.

Regardless of the approach you take, be mindful of how you are using email and what types of content you are sending to avoid being placed on a blacklist in the first place.

Common reasons for an email bounce back

When you receive an email bounce, this typically indicates that there is a delivery issue. Depending on the nature of the bounce message, there might be a quick way to figure out what the problem is and how to fix it. ESPs provide tools that allow you to see the email address status and availability of contacts in your account to identify common reasons for bounces:

Contact status types and availability of contacts in Selzy
Contact status types and availability of contacts in Selzy

In any case, some possible causes of email bounces include:

Email address error

Many marketers experience email bounce-back messages when their email service provider cannot find the address, either because it is invalid or expired. This can happen for a variety of reasons, including using unverified emails, buying an email list, or using an old email list. Other potential causes include entering an incorrect email address with typographical errors or formatting issues.

You will receive email bounce-back messages saying that the email account you are trying to reach does not exist. This can be seen in the image below.

Email address error example

Keep in mind that some users may deliberately provide false information in exchange for something offered online. If the bounce-back message is from a corporate address, it likely means that the user has left the organization and their account has been blocked by the IT department. In other cases, it could simply be that the user has an outdated email address and has transitioned to a new one.

How to fix 

  • Get the right email addresses by using double opt-in. This is a common practice in email marketing that involves confirming that recipients want to receive messages from you and verifying the validity and activity of their email addresses.
  • Do not buy email lists as these users have not agreed to receive emails from you. This will result in a high number of complaints which will lower your IP rating and could even get your IP address blacklisted. Besides, many purchased email lists contain a significant number of invalid addresses, meaning your budget for the mailing list would be wasted.

Full mailbox

One possible reason for your email being marked as undelivered is if your recipient’s inbox is full. Most email providers have a limit on the amount of messages that can be stored in an account at any given time, and if this limit is reached, new emails cannot be received.

Typically, you will receive a bounce-back message notifying you of this issue, which may look something like this:

Full mailbox issue example

How to fix

  • This is considered a “soft bounce” and will typically resolve itself over time as the recipient’s storage space becomes available again.
  • Another reason your email might get bounced back is that it’s taking up too much space in the recipient’s mailbox. This can happen if you’re trying to send an attachment that’s too large. Try compressing the file size, splitting it into multiple emails, or using an online file sharing solution like Dropbox.

Blocked emails

Bounce back is a common problem that can occur in email servers due to various reasons, such as IP restrictions imposed by government organizations, schools, or other industries. In these cases, recipient servers may block emails from certain IP addresses to maintain internal security and prevent unauthorized access.

If you are experiencing bounce backs when trying to send emails to corporate email addresses, this is likely because of their mail servers blocking your messages. In this case, you may receive an error message indicating that your emails have been blocked:

Message blocked email example

How to fix

You need to contact the person or company some other way and ask them to add your address to their safe sender list.

Auto-response is on

Out-of-office automated replies are a unique case that does not fall neatly into the categories of “soft” or “hard” bounces. These types of responses typically occur when a recipient is out on vacation, and they set up an automatic reply message with information that they will be back shortly.

Although this response may seem like your email has bounced, it has actually been delivered and your recipient will see your message when they return from their trip. Typical out of office automated replies often look something like this:

Auto-response email example

How to fix

If your email has not been read in a while, there is not much you can do except wait until it has been read.

If you are frequently receiving auto-reply messages, it may be a sign that the recipient is no longer interested in receiving your emails. It may be advisable to remove this contact from your mailing list in order to keep it clean.

Recipient server issues

Issues with the recipient’s mail server can often cause undelivered emails, ranging from server crashes and maintenance to overloaded servers or temporary outages. These issues may be categorized as either hard or soft bounces, depending on whether the email is ultimately delivered.

Recipient server issue message

How to fix

To overcome undeliverable emails, resend the message a few times and remove it from your bulk email list if it does not reach the recipient’s inbox after repeated attempts.

Other factors

If someone doesn’t want to receive your emails anymore, they can block or mark them as spam. If they’ve already blocked your email, you’ll get a notification saying it couldn’t be delivered:

Message delivery issue

Bounce backs can occur for a variety of reasons, ranging from unknown issues to problems with the IP address.

How to fix

To minimize the risk of an email bounce, monitor your IP address and take action if necessary. Additionally, remove any email addresses from your bulk mailing list that are experiencing frequent bouncebacks. By taking these steps, you can lower bounce cases and enhance the efficacy of your email marketing campaigns.

How to reduce your bounce rate

To prevent email bounces and ensure the success of your email campaigns, follow best practices and closely monitor any bounces that occur. If you notice that certain addresses are consistently bouncing, take action in order to mitigate this problem.

Regularly clean your email list and run re-engagement campaigns

Regular email list updates are an important step in maintaining good email marketing practices. As time goes on, the lists used to send emails may become filled with addresses that are no longer active or have other problems that can cause issues with deliverability.

Thinking about how to clean your email list? To keep it healthy and effective, review and remove any contacts that may negatively affect your bounce rate or overall engagement. Make sure your lists don’t contain any typos or syntax errors. Remove addresses that have been bouncing a lot (more than 3-5 times) and people who haven’t engaged at all (opened or clicked anything).

You can do it by requesting some more opt-ins from inactive users or manually checking the list for problematic contacts. To capture the attention of recipients who haven’t clicked on your emails in a while, consider running re-engagement campaigns. These campaigns can help you weed out inactive or “dead” accounts, while also nurturing those that may just need a little extra care and attention to get them back on board with your marketing efforts.

One possible approach might involve using targeted messaging, personalized content, and other engagement-boosting strategies to win over these potential customers.

An example of how this might look:

Re-engagement campaign example to weed out inactive/dead accounts
Source: Really Good Emails

Only send emails if you’ve got permission

When a new subscriber signs up for your emails, don’t add them to your mailing list right away. Consider permission-based lists when sending email campaigns. This means that you should only send emails to people who have consented to receive your campaigns, typically through double opt-in. This way, you can ensure that only active contacts are receiving your emails and as a result — reduce the number of spam complaints associated with your campaigns.

Your verification email can be simple and straightforward, just like the example from Twitch:

Verification email example
Source: Really Good Emails

Send emails regularly

To maintain a strong engagement with your email subscribers, communicate with them through regular messages continuously. This way, their email server will recognize your IP as active and less likely to mark your messages as spam. This means you are less likely to experience email failures or other problems.

Give the subscribers control

Your subscribers may not be interested in every type of email you send. To keep them from unsubscribing entirely, let them choose which types of emails they want to receive. For example, they can pick from the following types: announcements, promotions, tutorials, offers, events, newsletters, etc. Giving subscribers control over their email preferences can improve their experience and keep them on your list.

Bespoke Post is committed to providing a personalized experience for its subscribers. To do this, the company asks customers to set preferences so that they can receive more tailored offers.

Fill out your preferences email
Source: Really Good Emails

Authenticate your emails

Improving your email deliverability and reducing bounce rates involves authenticating your email domain with methods such as SPF, DKIM, and DMARC.

These techniques help email service providers to verify the authenticity of emails received, allowing them to more confidently accept messages from reputable senders. This improves sender reputation and helps recipients’ servers to better assess the quality of incoming messages.

Use list segmentation and personalization

As your email list expands, you may find it difficult to determine what your audience wants. Your recipients will not all want the same type of content or frequency of communication. Having fewer people flag your messages as spam will lead to higher engagement, thus reducing your bounce rate.

But if you want more personalized content, you should segment your email list first. By using automation tools, you can take list segmentation a step further and send custom-tailored emails. Some ways to segment include engagement level, demographics, age, or position in your sales funnel.

This is what Bombas does by sending targeted messages to clients who have already purchased from the company.

Targeted message example
Source: Sleeknote


Email marketing can be tough, especially when you’re just starting out to promote your business. Email bounces are a common problem for many businesses. These unwanted messages indicate that one of your emails has failed to be delivered, usually due to privacy issues or other technical difficulties. It’s important to accept that bounces are going to happen no matter what.

However, there are ways to reduce the number of bounces you get. By carefully reviewing your bounce reports and removing any non-responsive email addresses, you can make sure your emails are reaching the people they’re supposed to.

The primary conclusions are as follows:

  • A high email bounce rate is bad for your reputation and future campaigns.
  • Keep your email bounce rate as low as possible, ideally under a rate of 2%.
  • Ways to reduce your email’s bounce rate include cleaning your list regularly, having a permission-based list, sending emails often but not excessively, using authentication, segmenting your lists, and implementing email preferences.
  • By reducing the email bounce rate, you improve the performance of your campaigns and increase the chances of success of future campaigns.
12 May, 2022
Article by
Irene Dmitrieva
As a marketing copywriter, I have experience creating compelling content for websites and social media posts. My background in market research helps me ensure that my copy is both on-brand and data-driven. I am excited to bring my skills and experience to Selzy team and help drive success for this company.
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