Why is my camera screen black

[Maryjim]

I have a Samsung S7 Edge and my camera screen is black and the app won't open does anyone have any idea why this is happening

 

[belodion]

Welcome.

One possibility is hardware failure of some kind, but there are several kinds and it would need further testing before a diagnosis could be made.
Also, does the trouble persist in Safe Mode? If so, you could try another camera app from the Play Store.