Help Samsung S6 screen blinks (black with x in the corner) and makes sound

[Palves]

Hi,

Since a few days ago my S6 will randomly flash a black screen in one white x in the bottom left cornet plays a sound and again with a white x in the bottom right and then goes back to normal...

I did a factory reset and it keeps doing it.

Thanks in advance

 

[renniedoodle]

Mine is doing the exact same thing now- and also doesn't charge sometimes unless I restart it. Especially after it has done this. Did anyone ever find a solution?