: Ensure a microphone is connected and that you have granted the browser permission to use it. WebRTC registration sometimes fails if no audio input device is detected.

From an administrative perspective, the most effective fix is often disabling on the local router. If the error persists, switching the transport protocol from UDP to TCP or TLS can help bypass restrictive firewalls, as these protocols are more "firewall-friendly" and provide a more stable connection for signaling data. Conclusion

The WebRTC line is not registered, which may cause issues with real-time communication functionality.

If after all steps the error persists, – that allows a more specific fix.