550 Administrative prohibition

[kdarray]

My personal email address on one of my servers, has today, started receiving this message which I don't understand.

Remote-MTA: DNS; mail.mydomain.com
Diagnostic-Code: SMTP; 550 Administrative prohibition

How do I get off this administrative prohibition please.

[webignition]

You should begin by checking for any more specific errors in /var/log/exim_rejectlog

[tuxdesk]

If this is not the case, check the forward under /etc/valiases/$domainname for any typo's.
Make sure the mail inboxes exist under /home/$user/mail/$domainname/$mailuser/inbox

[kdarray]

There was no joy in exim_rejectlog. However, there was an error in the forwarding info in /valiases/$domain

Thanks so much for your help!!!