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Email bounces: causes and solutions

  • Updated

In this article, you will learn: Why an email might bounce, what a "Transient" bounce with a "General" subtype means, and what steps you or your customer can take to resolve the issue.

Topics covered in this article:

Fast lane:

If an email bounces with a "Transient" bounce (General subtype), the issue is temporary and related to the recipient's email. Here’s what they can do:

  • Check if their mailbox is full.
  • Verify if their email server is down or experiencing issues.
  • Whitelist the sender’s email address.
  • Check the spam/junk folder.
  • Contact their email provider for further assistance.

What does a "Transient" bounce mean?

A "Transient" bounce with a "General" subtype means the email could not be delivered due to a temporary issue on the recipient's side. This might be caused by their email server being down, too busy, or having custom restrictions that prevent the email from being received. Unlike a "Permanent" bounce, which means the email address is invalid, a transient bounce suggests that the issue might resolve itself after some time.

Possible reasons for the email bounce

The most common reasons for a transient bounce include:

  • Recipient’s email server is temporarily down – The server may be undergoing maintenance or experiencing technical issues.
  • Mailbox is full – If the recipient has exceeded their storage limit, new emails can't be delivered.
  • Spam filtering or blocking – The recipient’s email provider might be blocking or filtering the email as suspicious.
  • Custom restrictions – Some email providers have strict settings that might reject automated or bulk emails.

Steps to resolve the issue

Since the issue is on the recipient’s side, they can try the following solutions:

  • Check their mailbox – Ensure there’s enough space to receive new emails.
  • Verify their email server status – If the provider is experiencing downtime, they may need to wait and try again later.
  • Whitelist the sender – Adding the sender’s email to their safe senders list can prevent filtering issues.
  • Check spam/junk folders – Sometimes, the email is received but marked as spam.
  • Contact their email provider – If none of the above works, they should reach out to their email provider for further support.

Since the bounce is happening on the recipient’s side, we cannot resend the email successfully unless the issue is resolved on their end. If the problem persists, using an alternative email address might be a solution.

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