Sorry for the late reply. Unfortunately, your device has been tampered with, without your knowledge. Right now, I don't know any solution for this. So I can only answer your doubts.

Turn off your device, then enter "Download Mode". Once in "Download Mode", press "Continue" and you will be taken to a screen with numerous information. Look for "Knox Warranty Void" and you should see if you have tampered with your device. If it sho...

1) How did this happen?A)You have rooted your Samsung device and this has tripped your Knox.2) Is there a way to fix this?A) No, there isn't. After tripping your Knox by rooting or flashing unofficial kernel, you will no longer have access to most Kn...