In January, my wife bought a Samsung Galaxy S6 in France and received a T-mobile device. She had no problem to use it until 2 weeks.
After a reboot the phone have a screen about Network Lock and she can not use it as always with her simcard.
We had looking for where we can put an unlock code but we found nothing, and we do not understand why the phone is blocked when she used it without worry for 4 months
Have you any idea about that ? How can I unlock the phone from France ?