Why does my camera keep saying "Warning Camera Failed"?

[AC Question]

I have a samsung galaxy s4 mini. I have been having this problem for quite a while. Everytime I try to use the camera it fails to work. I even tried resetting my entire phone, deleting all data, cache, also i even reset my phone to factory reset, still i have this problem. I've tried everything online but nothing helped so far. Can some expert please help?