All of a sudden one of my clients has been having clients getting bounce backs that have this information in it.
5.1.0 - Unknown address error 550-'5.7.1 Unable to relay firstname.lastname@example.org
The server has no errors in the event viewer. There does not appear to be anything wrong with exchange, I even checked with the mail filtering and that appears to be working fine. I have even checked the receiptant policies just in case they have changed and they haven't. I am running out of opitions and I am losing my mind on this problem because it just happened all of a sudden and it is not constant. I need help BAD.