this is a 4k tv, so unless there is some problem with the tv and/or the plex app, it should be able to play 4k.
it won’t however, play HD audio.
It may also not like certain types of subtitles.
so try 2 things;
- make sure the audio stream is dolby digital/dts 5.1 or stereo
- make sure subtitles are disabled
please also read the entire thread @ Plex, 4k, transcoding, and you - aka the rules of 4k - a FAQ - General / General Discussions - Plex Forum
