...it happened a week ago from one of our mail server in the region. take note that both servers are in the same domain. when we try to send a message from mailserver1 [with an option trace entire path] to mailserver2,,,mail router will just inform that it reaches mailserver2, but not the person's mailbox. sending message using internet address [with firstname.lastname@example.org]...assures delivery of mail from mailserver1 to mailserver2,,,but not when selecting name from NAB [i.e. "fname lname/DOMAIN"].
...can you please guide me through possible cause and solution to this problem.