Calls from Firefox are failing to connect. This is caused by the connection popup window being removed from focus (put behind another window), getUserMedia is triggered but a callback is never called.
Set up a call from Firefox, here is the sequence of the problem:
1. Press assist button
2. Connection pop up appears (with auto accept media prompt turned on).
3. Switch back to landing page (putting the pop up behind the landing page).
4. Video window on landing page will get stuck in "connecting..."
5. Call will fail.
Keep the popup window on top (in focus) until the call is established.
Please see Mozilla Bug report for reference of this issue: