LMS players not discovered as DLNA renderers

Hi,

I'm running LMS 8.3.1 in a docker container and want the connected players (several squeezelite instances) to be available as DLNA renderers, so I can play audio from my Android phone using LMS.

Unfortunately, the players are not discovered within my network. The plugin "UPnP/DLNA Media Interface (v1.0)" by Andy Grundman is activated.

I guess it may have to do with me running the LMS in docker without using host network.
Which ports are required for DLNA?

Any hints, how I can get this running?


Thanks.