My Samsung Galaxy S6 keeps going to a black screen and then my home screen?

[AC Question]

Whenever I unlock my phone it constantly goes to being a black screen and to my home screen. It keeps switching rapidly. I've tried shutting it off and restarting it but it keeps doing it. It's been doing this for 4 hours.

 

[lucianus_luciferus]

while the phone is on keep the power button pressed for about 10 seconds until the phone restarts itself