Bought an unlocked Google Pixel and it worked with ATT. It also worked with TMobile sim My friend inserted his Sprint sim and it was detected, but calls would not go thru. Since then, my phone shows an invalid sim error - and to ask Sprint if device can be unlocked.
Since I am not a Sprint customer, the customer care were not able to find any information. ATT customer service confirmed that the phone is registered under my number.
I am clueless on how to resolve this.
Asking here coz Sprint community is read only.
Any help is greatly appreciated.