Bounceback errors in cPanel Webmail occur when an email you attempted to send wasn’t successfully delivered to the recipient. These messages usually include an error code and an explanation of the issue. Common causes of bouncebacks include incorrect email addresses, full inboxes, server problems, or the message being flagged as spam.

Common Bounceback Errors and Causes

1.Incorrect or Invalid Email Address
The most frequent cause. The email address may be:

Misspelled

No longer in use

Associated with a deleted account

2. Full Mailbox
The recipient’s inbox has reached its storage limit, blocking new messages.

3. Server Issues
The recipient’s mail server may be:

Down for maintenance

Overloaded

Experiencing technical issues

4. Spam Filtering
The email may be flagged as spam due to:

Suspicious content

Poor sender reputation

Blacklisted keywords or attachments

5. Blocked Sender or IP Address
Your email address or server IP may be blacklisted by the recipient’s mail server.

6. Incorrect Email Routing
Misconfigured MX records or email routing settings (e.g., in cPanel) can prevent proper delivery.

7. Large Attachments
If attachments exceed the recipient’s server size limit, the email may bounce.

How to Troubleshoot Bouncebacks

1. Verify the Recipient’s Email Address

Double-check for typos or outdated addresses.

2. Check for Server Outages

Review the bounce message or check server status; if it’s a temporary issue, wait and try again later.

3. Examine Error Codes and Messages

Bouncebacks often include error codes (e.g., 550, 552, 554). Look up these codes for specific meanings.

4. Consider Size Limits

Use a file-sharing service (like Google Drive or Dropbox) for large attachments or compress files before sending.

5. Check Email Routing Configuration

In cPanel, make sure the email routing settings match your domain’s MX record configuration.

6. Contact Support

If you’re unable to resolve the issue, reach out to your email hosting provider’s support team for help.