Email bounce back messages can be frustrating for any email marketer or sender. These messages indicate that the email you sent did not reach its intended recipient and has been returned to you. Understanding the different types of bounce back messages and knowing how to resolve them is crucial for maintaining a healthy email deliverability rate and ensuring your messages reach the inbox. In this comprehensive guide, we will delve into the world of email bounce back messages, their significance, common causes, and effective strategies to address them.

What is an Email Bounce Back Message?

An email bounce back message, also known as a bounce message or non-delivery report (NDR), is an automated email notification generated by the recipient's mail server to inform the sender that their email was not successfully delivered. Bounce back messages provide valuable information about the delivery status and reasons for the failed delivery.

Types of Email Bounce Back MessagesEmail bounce back messages are typically categorized into two types: hard bounces and soft bounces.

1. Hard Bounces

A hard bounce occurs when an email fails to reach the recipient due to permanent reasons such as:

Invalid or non-existent email address

Domain name does not exist

Recipient's email server is blocking incoming messages

Hard bounces indicate a permanent delivery failure and should be removed from your email list to maintain a healthy sender reputation.

2. Soft Bounces

A soft bounce refers to a temporary delivery failure that could be caused by:Recipient's mailbox is fullEmail server is temporarily unavailable

Message size exceeds the recipient's server limits

Soft bounces may resolve themselves over time, and it is recommended to attempt delivery again.

Common Causes of Email Bounce Backs

Several factors can contribute to email bounce backs. Here are some common causes:

Invalid or Non-existent Email Address: Sending emails to addresses that do not exist or contain typos will result in hard bounces.

Full Mailbox: When a recipient's mailbox reaches its storage capacity, further emails are rejected until space is cleared.

Server Issues: Temporary server problems can cause soft bounces. These issues could include maintenance, high server load, or network connectivity problems.

Blocked by Spam Filters: If your email is flagged as spam by the recipient's server or a spam filter, it may result in a bounce back.

Strategies to Address Email Bounce Backs

Resolving email bounce back issues requires proactive measures. Here are some effective strategies to address bounce backs:

Maintain a Clean Email List: Regularly validate and update your email list to remove invalid or non-existent email addresses.

Follow Best Practices: Adhere to email marketing best practices, including obtaining permission to send emails, using double opt-in, and providing clear unsubscribe options.

Monitor Delivery Rates: Keep track of your email delivery rates and bounce rates to identify trends and potential issues.

Segment Your List: Segment your email list based on engagement levels to ensure targeted and relevant content, reducing the likelihood of bounce backs.

Implement Feedback Loops:

Sign up for feedback loops provided by major ISPs to receive notifications when recipients mark your emails as spam.

Monitor Sender Reputation: Maintain a good sender reputation by adhering to email authentication protocols, such as SPF, DKIM, and DMARC.


Email bounce back messages are an inevitable part of email marketing, but with the right knowledge and strategies, you can effectively manage and minimize their occurrence. By understanding the different types of bounce backs, identifying common causes, and implementing best practices, you can maintain a healthy email deliverability rate and ensure your messages reach the intended recipients. Remember to regularly monitor your email list, follow industry guidelines, and stay proactive in addressing bounce back issues for a successful email marketing campaign.