Don - The solution that worked for me was a call to Verizon. Interesting that you have this problem after it has been working for 3 weeks, but nonetheless, call Verizon and tell them the problem. They need to provision you again. They will remove you from the data plan and put you back on. Don't factory reset, that probably won't help.
The only reason they will have you do factory reset is in case the phone will not provision correctly when the system is provisioned correctly. A way to reprovision the phone without going through the hassles of a hard reset is,
dial ##program (use the digits that correspond to program)
go to nam settings i thin it is, go to mdn and change it to 0000000000
then go to the mind settings and change it to 0000000000. hit menu, commit modifications (i think thats what it says). then the phone will reset, and then it comes back up, do *22800, wait for the chick and then press 1.