Lost password on Galaxy S2, can't shut down
To force the Galaxy Tab E to restart, hold the power and volume down keys for around 20 seconds. This has the same effect as physically removing the battery. If this does not work, attempt holding all four physical buttons for 20 seconds. After the device is turned off, start it up in the recovery mode by holding volume up + home + power. Highlight Wipe data/factory reset with the volume keys and select it using the power button. Select Yes and the tablet will be restored to factory specifications. Finally, select Reboot system now to restart the device.
During the setup process, Factory Reset Protection may kick in. Log in to the Google Account previously used on the device to disable it.