Be assured below given steps would help you out to solve the issue which you are facing:-
1) Safe Mode:- Power off the device > Press and hold the Power key for one or two seconds to turn on the device > When the Samsung logo appears, press and hold the Volume down key.(To exit safe mode restart your device) 2) Check storage:-Settings > Device care > Storage > Check available storage space. 3) Third party applications can also cause auto restart ( Uninstall the third party applications ). 4) Remove memory card and check :- Apps > Settings > Device maintenance > Storage > More option > Storage settings > SD card > Unmount. etc
If issue still persist please do send the log file via, Samsung member > Get help > Send feedback > Error reports > Select Symptom category. So that we can provide you the better assistance.(Note:-You are requested to send it within 15 minutes of problem occur).
