Licode problem with Firefox

After updating Chrome to v85 our clients failed to publish streams but we couldn’t find any error message (both on the server and client). Our investigation did not reach the result and we decided to upgrade Licode to the latest version (v9). However, our previous version was quite old (v5.4). Our issue with Chrome v85 solved when we upgraded it to the latest release but another issue raised up. Now we have problem with Firefox. The first client creates a room successfully. Once the second client is joined to the room this message is appeared:

WebRTC: ICE failed, add a TURN server and see about:webrtc for more details

We are using default configuration for the STUN server but it keeps throwing the above error.

Anybody can help us for this issue?