I’ve recently moved servers and instead of managing my own Plex install, I decided to go with the a docker install. It took seconds to sort out and I was very happy with it. That was until I enabled remote access. Suddenly, all my videos looks started looking terrible quality.
This has been resolved by going to Dashboard -> Settings -> Network and under “Lan Networks” adding the values “172.18.0.0/16,192.168.0.0/24,127.0.0.1″ (without the quotes).
You will need to work out your own values.
To work out the subnet for the plex container:
$ docker network inspect plex_default|grep Subnet
"Subnet": "172.18.0.0/16",
To work out the subnet for your local network (in the majority of cases),
$ hostname -I | awk '{print $1}'
192.168.0.25
So, this needs to be : 192.168.0.0/24