I have a related but possibly weirder problem (7105t, mail server is communigate pro, using BIS not enterprise, through T-Mobile):
* I can receive email fine
* I can send mail to people OTHER than those using my server -- mail which then immediately shows up in my sent mail folder on the server
* Users on my server (i.e., in my company) do not receive the emails I send, while everyone else does
My tech person, already peeved because I didn't get the company standard Treo, isn't much help but says the problem is I need to be able to configure the SMTP authentication and port settings ... which doesn't seem possible. Anyone a) have related problem, or b) know how to do this?