Why cant i use my t-mobile sim in my metropcs samsung galaxy j7 sim unlocked

[Android Central Question]

I had it working in my j7 before but then it went through some errors and factory reset itself and now its still sim unlocked but i cant use and sim in it but when there is no sim inserted it has full bars and it recognizes my sim is inserted but it doesn't let me text or anything and the service bars are x'd out

 

[B. Diddy]

Welcome to Android Central! Check to make sure the correct Network Operator is selected in the Settings>Mobile Networks menu, and also make sure the APN is correct for T-Mobile. https://www.androidcentral.com/what-apn-and-how-do-i-change-it