Hard Reset ZTE Grand X Max+

First method:

1. The device must be turned off, so press and hold Power button.
2. Now press the Power button, and wait until the phone turns on.
3. After that choose emergency dial, and type this: *983*22387#
4. Then from the menu in front of you select Erase Everything.
5. Done! Now your phone will restart.

Second method:

1. Press the Power button, until your device is on.
2. Then from the home screen open Menu and choose Settings.
3. After that select Privacy and tap Factory data reset.
4. Choose Reset phone and select Erase everything to begin hard reset operation.

Third method:

1. Switch off your device.
2. After that press and hold Volume Up + Power button.
3. Release held keys when you see new menu on your screen.
4. Then press Volume Down to select option "Factory reset", and press Power button to confirm.
5. Afterwards press Power button to enter option "reboot system now".
6. Good job!

WARNING !
Hard Reset will erase all of your data
All described operations you are doing at your own risk.