I just came here to say that this fixed my issue as well now have the official Plex Docker running Version: 6.10.3 Unraid. GPU is Quadro P2200 and I was having a similar issue no matter which docker I used for Plex it was all doing the same thing it would show up momentarily using the Terminal Command 'watch nvidia-smi' but then go away and would not start transcoding and Plex would just spin. I made sure to have all the correct settings. I for the life of me could not find the Docker Safe New Perms mentioned in my tools tab. So first you need to install from the Apps tab the App 'Fix Common Problems' then you will go to your Tools tab and see Docker Safe New Perms. Thanks for all the help and hope this helps clarify for someone new.