Also the docker image just stops itself after starting when I start with your parameters:
mattermost@mattermost:~$ docker run --name mattermost-webrtc -p 7088:7088 -p 7089:7089 -p 8188:8188 -p 8189:8189 -d mattermost/webrtc:latest
6977a58ad917d03ded04980764a3617b06b414b14420cc60390688b96db1dd1d
mattermost@mattermost:~$ docker ps
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
6977a58ad917 mattermost/webrtc:latest "/bin/sh -c /opt/j..." 4 seconds ago Up 3 seconds > 0.0.0.0:7088-7089->7088-7089/tcp, 0.0.0.0:8188-8189->8188-8189/tcp mattermost-webrtc
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
6977a58ad917 mattermost/webrtc:latest "/bin/sh -c /opt/j..." 22 seconds ago Exited (1) 16 seconds ago mattermost-webrtc
Looking into the log of the container, it shows that it is stopping for the very same reason. There is a STUN configured in the config of janus that does not work. But even if I remove it, I cannot get it running with Mattermost (see above).