Ever come across a situation in which the root mails are getting hung in the queue?
Even if you have configured a forwarder to another email address, the root mails tends to just stuck in the queue and pile up.
A closer look on the body of the bounced up mails will show the – “domain may not exist” error.
The problem was due to the fact that the server hostname was missing from the /etc/localdomains file.
Make sure the FQDN – hostname of the server is found in /etc/localdomains.