I’ve seen other threads which didn’t get resolved relating to my issue so I wanted to try again.
After an hour of playing films my tv says buffering and then eventually errors back to the film description screen, attempting to play again results in the same buffering and then failure back to the film description screen.
There was mention on the other threads of troubleshooting normal buffering issues which I thought might be the issue and as such now have my tv plugged in directly is Ethernet to a gigabit switch which the Mac Plex server is also directly Plugged into.
The mkv films are around the 3GB size, the Plex server is a quad core and with the gigabit switch I can’t imagine there is a network bottleneck, although the same issue happens over Wi-Fi.
Could it be a transcoding issue where the server can’t transcode fast enough?
If I turn the tV off and back on again and then resume the movie from the place it failed then it buffers for a bit and carries on playing fine.
How do I resolve this?
I’ve tried contacting support but just realised they no longer exist since I first purchased my Plex pass. 
