ATT Sim Card crash

[Cutehumor]

I got my wife a new ATT prepaid phone for xmas. well, I unlocked the phone so I could move her T-mobile sim card into this new att phone. The tmobile sim card in her new att cell phone works fine. but when I move the ATT sim card over to the old unlocked tmobile phone. it says "sim card crash". When I put the ATT sim card back into the new ATT phone, it works perfectly. So I know there is nothing wrong with the sim card. anyway to get rid of this "sim card crash" error. both cell phones are unlocked. I don't want to lose the $50 bonus airtime that came free with the new att phone.

 

[JHZR2]

How sure are you that the tmobile phone is truely unlocked? if it works in the ATT phone, why not just use it in that?

 

[Cutehumor]

yeah, the tmobile phone is unlocked. I verified by hitting *#7465625#. I think the att sim card is coded to only use on gophones. I'm gonna grab my wife's att phone to see if the sim card is unlocked