When I create a new Mailbox on the Exchange 2007 server you are unable to send to that Mailbox from the “Outside World”. For example, if you try to e-mail email@example.com from the outside world you will get the following error message (550 550 5.1.1 User unknown (state 14)). Here are a couple of things that get me. Number one you can e-mail out (Send) from that account to the outside world, however if the recipient replies or creates a new message to that account they get the message above. Next, this just started happening all of the sudden today. Also, note that I just created another account yesterday and had no issue, but today I do. Weird?? Any ideas what would be causing this??