I got it. It seems that T-Mobile changed their internet3.voicestream.com connection to block port 443. I revised my instructions
located here to reflect the change.
To change it if you already configured your phone:
1) Press PROGRAMS -> SETTINGS -> DATA CONNECTIONS
2) Press MENU -> EDIT CONNECTIONS
3) Select GPRS CONNECTIONS and press the blue action button
4) Select T-ZONES WAP and press the blue action button
5) Change the entry in the ACCESS POINT field from
wap.voicestream.com to
internet3.voicestream.com
6) Press DONE
7) Press DONE
8) Press DONE
9) Press DONE
10) Press DONE
11) Press the HOME key
Now try to sync again. I set mine up this morning and have been able to sync about 15 times today so far. Did I mention I love unlimited internet?