I decide to open my device and the problem was the conector was not connected correctly. I have pressed on the conector only, now it works fine.
It was probably a fall to the ground.
As you can read in his message he has tryed it already.
I had this camera error after upgrading to 7.6.15 (nougat rom), so maybe my phone is fake xiaomi device. I can not check it now with 'Mi Verification' apk because I have no camera.