Soft reset can resolve issues like continuous resetting/rebooting, device crashing, freezing, won't ring or vibrate, can't make or receive calls, 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. A soft reset won't affect data on the device.
Press and hold the Power button (located on the top-right edge with the screen up and the charging port facing down) until the 'Phone options' screen appears then release.
From the Phone options screen, tap Power off and restart.
From the Power off and restart prompt, tap OK. Allow several seconds for the device to power off. If the device is unresponsive/frozen, press and hold the Power button for approximately 10 seconds or until the device power cycles.
Press and hold the Power button (located on the top-right edge with the charging port facing down) until the device powers off (approximately 10 seconds) then release. Allow several seconds for the reboot process to complete.