Big Blue Button
From Organic Design wiki
Troubleshooting
ICE error 1107, video not working
After initial installation, room members couldn't activate video, all getting Connection failed: ICE error 1107, which is a known issue in Github. This is most likely that UDP is not getting through to the server. You can test UDP as follows:
On the target machine being tested:
nc -ulp PORT
And on the machine sending the tests:
nc -u SERVER PORT
Then type text and hit enter, it should be echoed on the server.
If it's not, check the firewall status and disable:
ufw status
ufw disable