Last night i was playing on my xbox one x just fine up until i got off at 3:30 am cst. I have been using 4k on my xbox for 2+ years now just fine, but a sudden switch on my tv where it said hdmi 1 now says xbox one and my tv wouldn’t allow my xbox to work until it was put into a lower resolution. It is running currently at 1080p but i would like to know why a 4k uhd compatible device isn’t being allowed to run at the 4k level by my tv
Did it recently update? Check under Settings->System->System update.