Administrator receives bounce email message to mailbox not registered in Plesk: This address no longer accepts mail

Symptoms

• Administrator receives a bounce email message from Plesk server with the below text:

  This address no longer accepts mail.

• Email address from the bounce message does not exist in Plesk at Domains > example.com > Email Addresses.

• Action What to do with mail for non-existent users is set to Bounce with message at Domains > example.com > Mail Settings page:

  

Cause

Emails sent to non-existing email addresses are set to be bounced.

Resolution

This is the expected behavior for such settings. The bounce messages can be safely ignored.