How to establish a reliable data connection

 1. Power off the phone.

2. Press and hold both Volume keys, then press and hold the Power key at the same time.

3. Release the Power key when the device powers on.

4. Release the both Volume keys when the Android system recover menu appears.

5. Using the Volume keys, scroll to wipe data/cache and press the Power key to select.

6.Boot your phone and follow the set-up steps