What is the unlock network code for my Samsung on5 phone

[AC Question]

I need the unlock network code for my Samsung on5 phone to go from t-mobile to textnow... I placed a new SIM card in my phone and the upper left hand corner says NETWORK LOCKED SIM card inserted ... what do I do?

 

[B. Diddy]

Welcome to Android Central! See T-Mobile's unlock policy: https://support.t-mobile.com/docs/DOC-1588