Help Problems unlocking AT&T Galaxy S4 running Android 4.3

[thepcfacer]

I am trying to unlock an AT&T branded Samsung Galaxy S4 SGH-1337 that I purchased from someone on Craigslist. It is running Android version 4.3 and I have an unactivated AT&T sim card inside.

I use *#0011# to get into Service Mode (*#27663368378# does not work), but I cannot get into the Main Menu. I try selecting the Home button and pressing Back, but it doesn't go anywhere. I also try to enter 1 as the Key Input to get to the UTMS screen, but it also doesn't work.

Any suggestions would be greatly appreciated, thanks!

 

[Rukbat]

Why would you have to unlock an AT&T phone to run an AT&T SIM? If it's not working it's not a SIM-lock problem.

 

[thepcfacer]

I'm planning to use the phone in Europe and I'm trying to unlock it before I go. Should I wait until I get there to do it?

 

[thepcfacer]

Why would you have to unlock an AT&T phone to run an AT&T SIM? If it's not working it's not a SIM-lock problem.

I'm now in Switzerland trying to use my AT&T Galaxy S4 with a SWISSCOM Sim card, but it's still not working. I get a screen that asks for the 'SIM network unlock PIN'.

Any other suggestions?

 

[speedlever]

I think you're going to have to talk to AT&T to get it unlocked.

Good luck.