Email communication is an integral part of our personal and professional lives. However, there are instances when our emails bounce back, preventing them from reaching the intended recipients. In this comprehensive guide, we will explore the concept of email bounce backs, understand the reasons behind them, and provide practical solutions to address this issue effectively.

What is an Email Bounce Back?

An email bounce back, also known as a bounced email or non-delivery report (NDR), occurs when an email fails to reach its intended recipient and is returned to the sender's inbox with an error message.

There are two types of email bounces:

Soft Bounce: A soft bounce is a temporary delivery failure caused by temporary issues such as a full mailbox, a server being down, or a recipient's email server being temporarily unavailable.

Hard Bounce: A hard bounce is a permanent delivery failure caused by permanent issues such as an invalid or non-existent email address, a blocked email domain, or a recipient's email server rejecting the email.

Causes of Email Bounce Backs

Several factors can contribute to email bounce backs:

Invalid or Non-Existent Email Addresses: When an email is sent to an address that doesn't exist or contains typos or formatting errors, it results in a hard bounce.

Full Mailbox: If a recipient's mailbox is full and cannot accept any more messages, it leads to a soft bounce.

Email Server Issues: Temporary problems with the recipient's email server, such as maintenance or technical glitches, can cause a soft bounce.

Blocked Email Domains: Some email servers or spam filters may block certain email domains or IP addresses, resulting in a hard bounce.

Content or Attachment Issues: Emails containing suspicious attachments or flagged content by spam filters may be rejected, leading to a hard bounce.

Preventing Email Bounce Backs

While it is impossible to eliminate email bounce backs entirely, you can take proactive measures to reduce their occurrence:

Maintain a Clean Email List: Regularly clean and update your email list by removing invalid or inactive email addresses.

Use Double Opt-In: Implement a double opt-in process to ensure that subscribers provide valid email addresses and confirm their subscription.

Verify Email Addresses: Utilize email verification tools to validate the authenticity of email addresses before adding them to your mailing list.

Follow Email Deliverability Best Practices: Adhere to email deliverability guidelines, such as using a reputable email service provider, avoiding spammy content, and personalizing your emails.

Monitor Bounce Rates: Regularly monitor your email bounce rates to identify patterns or issues and take appropriate actions.

What to Do When Emails Bounce Back?

When you encounter email bounce backs, it's crucial to take the following steps:

Review the Error Message: Carefully read the error message provided in the bounce back email to understand the specific reason for the bounce.

Check Email Addresses: Verify the email addresses of your recipients to ensure they are accurate and properly formatted.

Resend the Email: If the bounce was due to a temporary issue, attempt resending the email at a later time.

Remove Bounced Email Addresses: For hard bounces, remove the email addresses from your mailing list to prevent further unsuccessful delivery attempts.

Contact Recipients: If necessary, reach out to recipients through alternative means to obtain updated or correct email addresses.


Email bounce backs can be frustrating and impact your email marketing efforts. By understanding the causes of bounce backs and implementing preventive measures, you can significantly reduce their occurrence. Regularly review and update your email list, follow best practices, and promptly address bounce backs to ensure successful email delivery and improve your communication effectiveness.