Okay, did you rooted it or did anything wrong with bootloader? If not , try to go to settings-security and privacy -more security settings - secure folder . Try to install from there... I think if you didn't tampered anything related to knox RM fuse ,it'll install smoothly. Keep me updated soon
Kindly reset factory data with backup then try to it's again. If you like please accept as a solution it's help to others users also, click on 3dots in my reply section and click on accept solution. Thanks.
