Reread everything and I see I have complicated the issue. I didn’t see any issues in your log to indicate network problems.
At the moment, Plex is known to not properly show remote access correctly. Port forward with UPNP turned off is best. As long as remote clients are working then all is ok, this is separate from DLNA.
DLNA only works on the local LAN, which gets back to the Docker config, Host mode is best so that DLNA doesn’t see 192.x.x.x as a different network from 172.x.x.x. Docs on the DLNA settings are a bit vague. Maybe AVAHI would help but I don’t know, I have it running on my router and Debian host. I’ll install the avahi-utils and explore a bit.
And there is a new server version to check out.
