How do i find out which service provider my Samsung GS7 is locked with?

[AC Question]

Recently purchased this phone off of Craigslist. I took it into Verizon to activate it and they told me that the phone was locked with AT&T or T-Mobile. I searched the IMEI with each provider and the phone wasn't found. I need a way to figure out who locked my phone so I can unlock it. Please and thanks

 

[nahoku]

If it's a branded phone, you should normally see the carrier name splash screen when you restart the phone. You could also go to About phone in settings and search google for the model number or baseband version to find out what carrier the phone belongs to.

 

[B. Diddy]

Welcome to Android Central! Also check the IMEI here: https://swappa.com/esn?ref=mobilenations&data1=UUacUvbUpU5684270. Make sure it hasn't been blacklisted.