All field mappings have been cleared and I have an unlimited data plan. I have set up the blackberry internet service on t-mobile's site and that part works (I get mails through the blackberry service), when I try to perform enterprise activation, it fails.

Nokia E-90 with latest firmware (300.x), BBC 4.0 (from nokia for business site) and my company runs BES 4.1.6

EDIT: Just confirmed that it was able to activate, but fails to send/receive mail on the account.