Almost all hdcp errors I've ever come across is because of the hdmi cable. Different hdmi cables are all different versions, they all look the same and none of them say what kind of hdmi cable they are printed on the actual cables. Kind of aggravating to me. I test hdmi cables with my ps4. I'll plug the ps4 into the TV with one cable, check to see if I can turn on HDR, if it works that cable is at least a hdmi 2 cable.
If you need a new cable I highly recommend bluerigger. It's the only one I'll buy anymore.
https://www.amazon.com/BlueRigger-Rugged-High-Speed-Cable/dp/B003XM1WE0
My Samsung is a 6 series. UN50NU6900B