Perform a soft, factory, and alternate master reset of the device.
INSTRUCTIONS & INFO
POWER CYCLE YOUR DEVICE: There are multiple ways to reset your device if you are experiencing issues. The first step is to power cycle your device. Press and hold the Power/Lock button, then select Power off. To turn the device back on, press and hold the Power/Lock button until the screen lights up. Note: If you are unable to power your device off or if it becomes unresponsive, press and hold the Power button for 10 seconds until it reboots.
RESTART YOUR DEVICE: If a power cycle does not resolve your issue, perform a device restart. Press and hold the Power/Lock button on the right side of the device, then select Restart.
FACTORY DATA RESET: If a restart does not resolve your issue, you may need to perform a Factory data reset (Master reset). This will erase all data on your device and restore it to factory settings. To 'Factory data reset' your device, swipe down from the Notification bar > select the Settings icon > scroll to and select Backup & reset > select Factory data reset > RESET PHONE > ERASE EVERYTHING. Note: A Factory data reset will revert the device back to factory settings. It will permanently erase all personal data, preferences, settings and content such as pictures, ringtones and apps that are saved to the device. It is recommended that you save (backup) important data before proceeding.
If you are unable to reset the device using the above steps, try the alternate master reset method. To perform an alternate factory reset, with the device turned off, hold down the Power/Lock button and Volume Up button at the same time for approximately 5 seconds until you see the ZTE logo, then release.
Once the recovery mode screen appears, press the Volume down button to highlight Wipe data/factory reset then press the Power/Lock button to select.
Press the Volume down button to highlight “Yes”, then press the Power/Lock button to select.
Once complete, you will be returned to the device reset screen. Ensure that Reboot system now is highlighted, then press the Power/Lock button to select.