I think I’ve found an issue with ICE candidate gathering on firefox 80.
We have a setup where the jitsi server (jicofo and videobridge) is only accessible via VPN. On Firefox 81.0 (64bit, Linux) the website loads fine but audio/video is not working. Looking at the ICE-stats in about:webrtc I discovered that the active vpn interfaces IP isn’t listed as a local host candidate.
The same setup works fine on Firefox 78, using the local ip of the vpn.
Also with other webrtc based services the vpn ip shows up as a local-candidate (host).