> Firefox has a different implementation of ICE than Chrome, so if your > configuration is incomplete, it's not impossible for one browser to > succeed and the other to fail. > In the present case, It is the contrary : all browsers succeed but firefox on some networks (mainly 4G SFR) > What does Galène say about the relay test in the log? I did try to reproduce using firefox on my IPAD with a 4G , I first got "pc ERROR: 2021/05/01 15:02:05 Incoming unhandled RTP ssrc(279383751), OnTrack will not be fired. mid RTP Extensions required for Simulcast » But the second try did work. Strange. Cheers, Fabrice.