What is Email Bounce? Types, Reasons, and Ways to Fix It [2023]

Have you sent an email and received an automated reversal notification? Email marketers handle this all the time.

What are email bounces, their common reasons, and how to fix them? What to do if many emails bounce?

In this blog, we will learn everything about email bounces.

What is Email Bounce?

An email bounce is a failure to deliver an email message to its intended recipient. When an email bounces, the server returns a message to the sender, indicating that the email was not delivered. There are many reasons for an email bounce:

1. Invalid email address: If the email address is incorrect or does not exist, the email will bounce.
   
   
2. Mailbox full: The email will bounce if the recipient’s mailbox is full.
   
   
3. Email blocked: If the recipient’s email server blocks incoming emails from the sender’s email server or domain, the email will bounce.
   
   
4. Email size: If the email is too large to be delivered, it will bounce.
   
   
5. Temporary errors: If the recipient’s email server is temporarily unavailable or experiencing technical issues, the email may bounce.

Sometimes, email bounces can be resolved by correcting the error and resending the email. However, if the problem persists, contacting the recipient or their email service provider for assistance may be necessary.

Types of email bounce

1. Soft Bounce

A soft bounce is a temporary delivery failure when an email message cannot be delivered to the recipient’s mailbox for reasons such as a full inbox or a temporary issue with the recipient’s email server.

Depending on the server’s configuration, the email server will typically make multiple attempts to deliver the message over some time. Soft bounces can be caused by various reasons, including:

• The recipient’s mailbox is full
• The email message is too large for the recipient’s mailbox
• The recipient’s email server is temporarily unavailable due to maintenance or technical issues
• The email message is being filtered as spam by the recipient’s email server

If the email server fails to deliver the email after multiple attempts, the soft bounce may become hard. However, if the issue causing the soft bounce is resolved, the email server will eventually be able to deliver the email to the recipient’s mailbox.

2. Hard Bounce

A hard bounce is a permanent delivery failure when an email message cannot be delivered to the recipient’s mailbox due to a permanent issue, such as an invalid email address or a blocked email domain.

The email server will immediately return the email to the sender with a permanent error message indicating that the email could not be delivered. The following reasons typically cause hard bounces:

• The recipient’s email server has blocked the sender’s email domain or server
• The recipient’s email server has been shut down or is no longer active
• The recipient’s email server is rejecting the email message due to policy or security reasons

Hard bounces require manual intervention to correct the error and resubmit the email for delivery. It is important to note that repeated hard bounces can harm the sender’s reputation and may cause their email messages to be filtered as spam by recipient email servers.

How do you know if an email is bounced?

Here are some signs that you might have received a bounce notification:

• You see an error message in your email client.
• You receive an email from your email service provider with information about the bounce.
• The email you sent appears in your sent folder with a note that it was undeliverable.
• The SMTP error message

Reasons for email bounces

1. Invalid or Non-Existent Email Address

If the email address provided by the sender is invalid or does not exist, the email server will not be able to deliver the email to the recipient’s mailbox. It can occur when recipients change their email addresses, or the sender mistypes them.

In such cases, the email server will immediately bounce the email back to the sender with a message indicating that the email address is invalid or does not exist.

2. Mailbox is Full

If the recipient’s mailbox is full, the email server cannot deliver the email to the recipient’s mailbox, causing the email to bounce back to the sender. It usually occurs when the recipient has not checked their mailbox for an extended period or when they have exceeded their mailbox storage capacity.

3. Email Size

If the email message is too large to be delivered to the recipient’s mailbox, the server will bounce the email back to the sender. The recipient’s email server usually sets the size limit for email messages, and if the email exceeds the maximum size limit, it will not be delivered.

4. Email Server is Down

If the recipient’s email server is down or unavailable, the email server will not be able to deliver the email to the recipient’s mailbox. In this case, the email server will attempt to deliver the email again after a certain period, depending on the email server’s settings.

5. Email Server is Blocking

Suppose the recipient’s email server blocks incoming emails from the sender’s email server or domain. In that case, the email server will be unable to deliver the email to the recipient’s mailbox, causing the email to bounce back to the sender.

It can occur when the sender’s email server is listed on a blocklist or the recipient’s email server has strict spam filtering policies.

6. Recipient’s Mail Server is Misconfigured

If the recipient’s email server is misconfigured, it may not be able to deliver the email to the recipient’s mailbox, causing the email to bounce back to the sender. It can occur when the email server settings are not properly configured or the email server software is outdated.

7. Email Content

If the email contains content that violates the recipient’s email server’s policies or spam filters, the email may be bounced back to the sender. It can occur when the email contains spam or suspicious content, such as phishing links, malware attachments, or misleading subject lines.

How to reduce email bounces

1. Check the email address

Verifying the recipient’s email address before sending an email is essential. If the email address is incorrect or does not exist, the email will bounce back to the sender. You can contact the recipient through a different channel, such as phone or social media, to confirm the email address.

2. Verify the email list

It is crucial to maintain an up-to-date and accurate email list. Remove any invalid or non-existent email addresses from the list regularly to reduce the likelihood of future bounces. You can use an email verification tool or service to validate the email addresses and ensure they are correct and active.

3. Reduce the email size

If the email message size is causing the bounce, you can reduce the email size by compressing any attachments or using a file-sharing service to send large files. It will help ensure the email is delivered to the recipient’s mailbox without issues.

4. Monitor email server logs

It is important to regularly monitor your email server logs to identify any bounce messages and troubleshoot the root cause of the issue. By analyzing the bounce messages, you can determine the reason for the bounce and take the necessary steps to fix the issue.

5. Improve email content

If the email is bouncing due to content-related issues, you can revise the email content to ensure that it complies with the recipient’s email server policies and spam filters. Avoid spammy words or phrases, misleading subject lines, or any content that can trigger spam filters.

6. Contact the recipient

If you cannot resolve the issue, you can contact the recipient through a different channel to confirm if they are receiving your emails and if there are any issues with their email server. It will help you identify whether the issue is on your or the recipient’s end.

7. Use an email verification service

Consider using an email verification service to validate email addresses before sending emails. An email verification service can check the email address for validity, activity, and deliverability, reducing the likelihood of bounces and improving the deliverability of your email campaigns.

Conclusion

To minimize the risk of email bounces, it is recommended to maintain an updated and clean email list, regularly monitor email server logs for bounce messages, and follow best practices for email marketing and communication.

By following these ways to fix email bounces, you can improve the effectiveness of your email marketing campaigns and ensure that your emails are delivered to the recipient’s mailbox without any issues.

FAQs

1. What is an email bounce?

An email bounce is a failure to deliver an email message to the intended recipient. The email can bounce back to the sender for various reasons, such as invalid email addresses, a full mailbox, or spam filters.

2. What are the types of email bounce?

There are two types of email bounces. A hard bounce occurs when the email cannot be delivered due to permanent reasons, such as an invalid email address or a non-existent domain. A soft bounce occurs when the email cannot be delivered for temporary reasons, such as a full mailbox or a temporary server issue.

3. How can I prevent email bounces?

To prevent email bounces, you can maintain an up-to-date and accurate email list, use an email verification service, avoid spammy words and phrases, ensure that your email complies with the recipient’s email server policies and spam filters, and regularly monitor your email server logs for any bounce messages.

Also Read:

• 19 Best Email Marketing Software and Tools
• 23 Best Email Marketing Tools Compared
• 14 Best Email Marketing Platforms [Features & Pricing Compared]
• 6 Advantages of Email Marketing you Should Know in 2023
• What is Email Marketing? Definition, Type, and Benefits