Originally Posted by larrylynch53
By the way, these are email addresses that, prior to the October change, were receiving emails from my Blackberry with no trouble.
Exactly! Starting October, after with T-Mobile upgrade, email from your blackberry to these email addresses started to arrive from what looks like different mail server than before.
An overly paranoid anti-spam system may conclude that somebody is faking your name and sending what could be a spam signed by you.
The best course of action is to complain to administrator of recipient mail server. Tell them your emails are wrongly rejected, and ask to fix it.