WebRTC signaling not working on Firefox

[DoubleSept]

Which demo project is affected:
web_rtc_signaling

OS/device including version:
Windows 10, Linux (Ubuntu 20.04)

Issue description:
When I start the WebRTC signaling demo, I cannot join a room when I use Firefox, the first part is made correctly but the Candidate messages are never sent (see screenshots).

I am very new to WebRTC so I'm not able to explain it further but everything is ok when using Chrome or a native app.

Screenshots of issue:
I added logging messages to check what infos are sent and received

Firefox:

Chrome:

[DoubleSept]

Sorry for the time lost, it works when using WebSocket Secure (wss).

Even on localhost I think firefox is preventing .... something... that Chrome allows.

I do not close as maybe it could still be a bug with simple websocket or something we need to add to documentation.