1. Please press and hold the power button and the volume down button at the same time for more than 7 seconds to restart the device; If it is a mobile phone with detachable battery, please press and hold the power button for 8- 10 second to restart the machine. If it fails, turn off the battery, take it out, and then plug it in again.
2. If the problem still exists after restarting the machine, it is recommended that you take the purchase invoice, maintenance card and machine to Samsung Service Center for inspection.