A soft reset can resolve issues like continuous resetting/rebooting, device crashing, freezing, device locks up, and keypad doesn't respond.
A soft reset (turning the device off then back on) is similar to restarting a desktop computer and is one of the first steps in troubleshooting a device.
In most cases, a soft reset won't affect data on the device, unless the battery is very low.
Press and hold the Power button (located on the back).
Tap Power off.
Simultaneously press and hold the Volume Down button (located on the left edge) and the Power button (located on the back) until the device powers off (approximately 5 seconds) then release.
Allow several seconds for the reboot process to complete.