Trouble Using an Unlocked Galaxy S6 on AT&T

[klgh07]

I recently bought my husband an unlocked Galaxy S6 that used to be a US Cellular phone (bought on Groupon).

I did have to create a new APN to use on AT&T. I did this before on his old Galaxy S5 and once I did that he never had any problems. I configured these both the same way but he's having trouble dialing numbers that have +1 before the area code, and he can't connect to his voicemail (but he gets notifications that he has voicemail)

I can't find a good solution to this problem. Are there more settings I need to change? Help!!

 

[lucianus_luciferus]

there are a few things you can check. see if there is an area code set. also check that the voicemail number is set correctly