what browser / device are you using? this is not something I encountered when trying with a few different ones :/
When I click on a room, the URL changes, indicating I might have joined the room, but I don't get any audio. No audio icon on the tab. Can't hear anything.
Console says "WebRTC: ICE failed, add a TURN server and see about:webrtc for more details"
I don't have WebRTC specifically disabled that I recall, I thought I've taken video calls in this Firefox before. Hope this report helps!