Ok, this may be a little confusing.
Company has 8 exchange servers throughout states. We have one LOCAL server called "MAIL" which has GFI Essentials installed on it. It also has IIS installed and running and under Default SMTP Virtual Server, it has "Mail - as local" + two other domains (as remote) Domain1 & Domain2 (it's just two variations of our domain name) as virtual servers.
Under "Mail" all that is set up is a DROP directory.
1st domain has allow incoming mail to be relayed to this domain & forward all mail to smart host (10.x.x.x)
2nd domain - same settings.
Now on our truly MAIN Exchange Server - Domain1, all the 8 Exchange servers are listed. Under Default SMTP Virtual Server there is no information entered there. And Domain1 IS the Smart Host.
We have a user who has been receiving the same email message over and over again, and so I contacted the dept of the company he's receiving from, and according to him, in his message tracking for that particular email message there is an error stating -> error transferring to "Mail" SMTP protocol returned permanent error.
All Queues have been checked, everything has been checked and none of us can figure out what's going on.