ffmpeg setting not working for x264 compatibility in television
notworking.mkv is 10-bit H.264 (yuv420p10le). I'm guessing the TV can't play that. You'll have to re-encode to the more common yuv420p for the TV to be able to play it. Basic example:

ffmpeg -i notworking.mkv -map 0 -c copy -c:v libx264 -vf format=yuv420p output.mkv