Unlocked Verizon iPhone 5s doesn't recognize AT&T sim (but recognizes T-Mobile)

[iMore Question]

Hi! I purchased a full-price Verizon iPhone 5s at Apple retail store. The phone was NOT activated during the purchase (as the recept states) - I specifically asked not to activate it, as I plan on using it on AT&T for now and maybe switch to Verizon later if I move to a larger city where Verizon is better than AT&T. The phone had Verizon nanoSIM. I also asked for and got free AT&T and T-Mobile nano SIM cards at the store. The phone recognizes both Verizon nano SIM (a message pops-up asking to call Verizon;'s 1-800 number to activate is) and T-Mobile nano SIM (get a voice message asking to activate it), but when AT&T nanoSIM is put in, it reads "No Service". Tried resetting the iPhone 5s - disin't help. What is the problem with AT&T? And, of course most importantly, how can it be fixed? Thanks a lot for any suggestions!! (And please excuse my ingorance if I'm posting this in a wrong thread...)

 

[Just_Me_D]

re: Unlocked Verizon iPhone 5s doesn't recognize AT&T sim (but recognizes T-Mobile)

Is it possible you have a faulty SIM for AT&T? Have you tried calling AT&T to activate the device on their network?