1 user uses a mac with the mac mail app to get into exchange when in and out of the office. They say that more and more, they get a message that the app can't connect to the server to send mail, and uses their mac.me? email address to send mail. Then it's not in his sent folder.
At first he said it was at hotels (and not total failure. It'd be 10 minutes failing, 20 success, etc.) but now it's even in the office once in a while?
Any advice on how to troubleshoot this?