.I have iphone 6 . I used this device on Orange Romania and worked perfectly. I reset it and now says he can not activate it. I checked the IMEI and he is encoded on tmobile uk. why?
This is Tmobile USA so you need to go thr the UK board but my guess is your phone was jailbroke, not unlocked,so when you updated the phone it locked it.
Retrieving data ...
Manage your T-Mobile account
Use the T-Mobile App or your My T-Mobile account
We're here to help