Firefox has issues detecting camera and microphone when trying to use several WebRTC services.

https://appear.in works now (did not work until last release of firefox).
But e.g. https://meet.jit.si does not and there is no message in xterm (where firefox was started from); it just displays a generic icon and no video; trying to play with the video on/off and mic mute/unmute buttons does not result in any output on the console.

Trying the relatively new built-in Firefox "Hello" (which is WebRTC), I get the following error (starting firefox from xterm):

/* Console output starts here. */
console.error: Loop: 
  Loop hawkRequest error:
Object
    - code = 400
    - errno = 203
    - error = Can't update status for a room you aren't in.
console.error: Loop: 
Object
    - code = 400
    - errno = 203
    - error = Can't update status for a room you aren't in.
console.error: Loop: 
  Loop hawkRequest error:
Object
    - code = 400
    - errno = 203
    - error = Can't update status for a room you aren't in.
console.error: Loop: 
Object
    - code = 400
    - errno = 203
    - error = Can't update status for a room you aren't in.
console.error: Loop: 
  Message: Error: Callback function was lost!
  Stack:
    invokeCallback@resource:///modules/loop/MozLoopAPI.jsm:138:8
injectLoopAPI/api.getSelectedTabMetadata.value/onPageDataResult/<@resource:///modules/loop/MozLoopAPI.jsm:955:13
LoopUI.getFavicon/</xhr.onload/reader.onload@chrome://browser/content/browser.js:5037:49

Object
    - url = https://bugs.freebsd.org/bugzilla/enter_bug.cgi?component=Individual%20Port%28s%29&product=Ports%20%26%20Packages
    - title = Enter Bug: Ports & Packages
    - previews = Array []
    - microdata = {"items":[]}
    - favicon = data:image/x-icon;base64,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
console.error: Loop: 
  Message: Error: Callback function was lost!
  Stack:
    invokeCallback@resource:///modules/loop/MozLoopAPI.jsm:138:8
injectLoopAPI/api.getSelectedTabMetadata.value/onPageDataResult/<@resource:///modules/loop/MozLoopAPI.jsm:955:13
LoopUI.getFavicon/</xhr.onload/reader.onload@chrome://browser/content/browser.js:5037:49

Object
    - url = https://bugs.freebsd.org/bugzilla/enter_bug.cgi?component=Individual%20Port%28s%29&product=Ports%20%26%20Packages
    - title = Enter Bug: Ports & Packages
    - previews = Array []
    - microdata = {"items":[]}
    - favicon = data:image/x-icon;base64,iVBORw0KGgoAAAANSUhEUgAAABAAAAAQCAYAAAAf8/9hAAAC/UlEQVQ4jXXTe0hTURwH8HOvmnNbWsuUcjm0bU6ZppX2ILJCE4YIFVb+IRIG9jCjRC0kahSsQorsYaOgpNRCrQwyKXJpq5SsgZormxnZNLNczTLSeb/9Zg8w7AefPy7n9zjn3HsZY4wjs0kAmxhiuVwe5BYYGCj5Z82fBBHe/RCa7yttv70ls3tbwpJjWlVo8gG9vshkMj22Wq3dHW1tbxrv1zcfKy4uWhgdqducnHD09s5s256pkpdUq3Y3UOoZ63seqQZulmNwoHd0DBPDaTajx3gCzoG3oxiw401GGgyMfaRazfh+NkgkZaZlSzBmf0fpAoThIYwNvYfL+RnCiBMOy2MMPqgFXCNwZKWjxscbm4KDK38fn84gk62ztzwBRochuH7AZe+Bq7MJo621+NZcRw2ewV5dgeGNOtQzhus6HeYplel/b2RDaqoe3R0QHL0QPtngKjXAlbEcH2NDYFGpUR8ejpr4eJRp1CiZI0eD4RDS0tOP/6n3Pr1/f4NgOg/hywt8K0yBU8bgpEmdpJFUEyM5KJFil1KFwylJKNq7u4Vqp7obBFbszbU5sqLxNX8x+hUMdvZLM6kjZeQEoZHYx3EokIhwuTDnHROJFOMNLmRvtb0O5tEfxtCn5McnW0ktKSel5BqhW0MBKZGJcceopxmiEHcDH8OOnIdmhQxdcpoczqPDl8MjSrxILpG7v3dyiuSR53mrUVl13EK1vr8uMS3t6K2kRDSJGF7RTrpUPMxShmJKriE3yBVyklyd6Qk0FyFz66Yzf9/CFKlUa8zN7asTe8Pix9A2h0d7GI87Ch73ZnColXEwB3NojeHQl6qB+eSRQS+xb+yEj3v+okXbq9auERo8GJpoeksQh6caHq8WeKBnqQcGVzAIGf7oLSlA3MK4fDZZaKOics6ujHdY5AGwTfeEdRaPD3Sc7yu8IeQGwWxYPxQXE1Pw5yeaNLzE4vmJ2oiSAxGaNqNW3V+xStVvzFS0r9eFnPPy8Yn7b+Ek4UfmEiWZ9r+kn2mUnAx1MMt2AAAAAElFTkSuQmCC

/* Console output ends here. */

Thank you for the support!