If you are experiencing this issue and you are using MacOS, please refer to the MacOS specific section
If this happens, there could be numerous reasons.
Check that you have hardware-acceleration turned on, within OBS, and have updated your graphic drivers
Ensure that you are not behind a VPN or firewall. Symmetrical firewalls may block OBS.Ninja traffic
If on macOS, use the Electron Capture application instead of the Browser source used by OBS (Also ensure you are running OBS v26.1.2 or newer!)
Try using a VPN, such as Speedify, to bypass any networking firewalls that your ISP may have enabled.
If you are on cellular, try connecting to Wi-Fi instead.
Ensure your are using a compatible browser (Safari on iOS or Chrome on Android)
Older iOS devices do not work
Check to make sure your TURN server supports IPv6. The ones I provide should support it though. Check test.webrtc.org
Firewalls may be setup that block traffic of this type. Talk to your network administrator Other problems? Check test.webrtc.org and see if anything is marked as "RED". You can also try different networks and see if that helps.
In the meantime, OBS.Ninja/old is up, and will remain up until I can resolve all the issues with the new release. This may solve your issue temporarily. So if you have this problem , where you see the fullscreen video, but it is just grey and spinning, then it could be a network issue.