Why won't my I-13 or I-16 device accept my product key after factory reset?
After factory reset, all software reverts back to the versions on the image that is stored on the device. To exit the Configuration Manager that runs after reset, power off the device then boot back up. Once it finishes booting up, connect to WiFi and run Update Notifier.
Once Update Notifier finishes installing updates run Configuration Manager to complete the device's setup.