One of such ways that Google and its partners use to add security to Android devices is called Factory Reset Protection or FRP. In order to work, FRP must be activated on the device first.
Oct 31, 2018 · Go to your phone Settings and search for Backup & Reset or Reset for some Android devices. From here, choose Factory data to reset then scroll down and tap Reset device. Enter your password when you’re prompted and hit Erase everything. Upon removing all your files, reboot the phone and restore your data (optional).