Quick answer
Use Default Address to reject mail addressed to nonexistent mailboxes on a selected domain. A rejection message does not delete a valid mailbox or change its password.
Applies to
For an email-enabled Interactive Online cPanel service. If Google Workspace, Microsoft 365 or another provider handles the domain's mail, manage that service there. Confirm the domain and complete mailbox address first.
Steps
- Open Email > Default Address and select the domain. Record the current setting so you can restore it.
- Select Discard the email while your server processes it by SMTP time with an error message, or the equivalent rejection option shown. Avoid silently discarding mail when you need a clear failure.
- Enter a concise error such as No such mailbox. Review the domain and save with Change.
Check the result
Send a controlled message to a nonexistent address and check the rejection. Separately confirm a real mailbox still receives mail.
Troubleshooting and support
If a valid address is rejected, confirm the mailbox or forwarder exists and that the domain's MX records reach this mail service.
If the problem continues, contact support from the account that owns the service. Include the domain, exact error, time and time zone, tool name, and a redacted screenshot. Keep passwords, private keys, cookies and private message content out of the ticket.
Video tutorial
The original video is preserved. Its interface or product version may differ from the written guidance above.
Related help
Official references
Written content reviewed November 1, 2026. Menu availability depends on the product version, permissions and service.
