[Chet62]

Okay, this is a weird one.
The internet browser on my MT4g just doesn't want to work on the T-Mobile network. It also won't sync anything.
Now, I'm getting a strong 4 bars and the H signal. My wife's 4g with the same settings is working just perfectly.
On wi-fi the browser and sync's work, but that doesn't do much good when away from the house.
I've cleared the cache, etc., restarted the phone, etc...
Any other ideas?

Okay....nevermind, I found the problem.

In an attempt to get the wi-fi to work at my workplace where everything is behind a proxy, I had accessed the proxy setting through the voice dialer. (Which didn't work, by the way.) When I deleted that proxy setting, my internet browser worked again.

It is still absolutely insane that you can't enter a proxy setting for wi-fi networks on this phone.