Troubleshooting: Error 20004 – Connection Established, No Media
Technical Breakdown
| Error Code | 20004 |
| Type / Category | Error / Media |
| Products | qualityRTC |
| Symptom | Call connected, but no audio or video is transmitted. |
What is this about?
In a WebRTC session, signaling (the handshake) and media (the video/audio) travel differently. Error 20004 means the handshake worked, but the media packets are being dropped or blocked by a security layer on your network.
Potential Risks
You will experience “silent” calls where you cannot hear or see other participants, and they cannot hear or see you, even though the call timer is running.
Suggested Troubleshooting Actions
- Restrictive Firewall: Corporate firewalls often block the specific UDP ports required for media traffic while allowing standard HTTPS (signaling).
Action: Ask your IT admin to verify that the required ports for TytoCare/WebRTC are open. - VPN Configuration: VPN tunnels may not be configured to handle real-time traffic, causing “hairpinning” or packet drops.
Action: Try disabling the VPN. If the media works without it, the VPN requires “Split Tunneling” for TytoCare traffic. - UDP vs TCP: WebRTC prefers UDP for media. If your network only allows TCP, media may fail to initialize or have extreme lag.
Administrator Tip: If this error is widespread across a single location, it is almost certainly a firewall rule. If it happens to a single remote user, have them check their home router’s “SIP ALG” or “Stateful Packet Inspection (SPI)” settings, as these can interfere with WebRTC media.