Firefox WebRTC has suddenly stopped working

[aguador]

I have been using talky.io about once a week under Cauldron. Sometime between 3 March and 11 March, something changed and I am suddenly unable to use either talky.io o jitsi meet. Although I have sound and video locally, it is neither sent to nor received from the second party. In addition, attempting to share a screen freezes my computers completely.

I have tried the sites disabling all extensions without success.

The machine I am using at the moment still has Win7 installed, and both sites mentioned above function under Windows.

Is anyone else experiencing similar problems or have any idea what the problem may be?

EDIT: I just tested with QupZilla and talky.io works normally except for not offering screensharing, so this is definitely something related to FF even though I do not remember any updates . . . .