Don't laugh at this one, I truely can't find the answer to this. The boss replied to a message from his Blackberry and got the response below. I did a search on the web for the error and most everything pointed to issues that don't apply here. My main question is are such messages are usually generated as a result of an issue on our side or their side? This has happened only once, but it was the boss' email. From: postmaster@xxxxxxxxxxxx <postmaster@xxxxxxxxxxxx> To: my_user@xxxxxxxxxxxx <my_user@xxxxxxxxxxxx> Sent: Tue Jun 15 15:24:31 2004 Subject: Delivery failure (recipient@xxxxxxxxxxxxxxx) Your message has encountered delivery problems to the following recipient(s): recipient@xxxxxxxxxxxxxxx Delivery failed 553 sorry, that domain isn't in my list of allowed rcpthosts (#5.7.1) No recipients were successfully delivered to. Paul Maglinger