In general, peruse this list carefully: Client says it won't play from "remote server", although the server is local
The requirement for Plex Pass or Remote Watch Pass to stream from a remote server is successively enforced in more and more client types.
“Remote” is defined by the server being located in a different LAN than the client.
Which means that even the “bridged” network access of a Docker container moves the Plex server within that container into a different LAN. The only way is to use “host network”.
