Start with the WebRTC Test (don’t skip)
Open the WebRTC Test and keep it open while you troubleshoot. It separates “WebRTC is blocked” into specific layers you can fix:
- Camera permission and camera preview
- Microphone permission and input meter
- Basic connectivity signals
- High-level codec support signals
When you change something, re-run the test. That keeps you from doing five fixes and not knowing which one mattered.
Quick decision tree (match the failing line)
Use this as a fast mapping between symptom and fix.
| WebRTC Test failure / symptom | Most likely cause | What to do next | Verify |
|---|---|---|---|
| Camera blocked / no preview | Site or OS permission, another app owns camera | Fix permissions, close other apps | WebRTC Test shows camera allowed + preview |
| Mic allowed but meter stays flat | Wrong device selected, OS muted, exclusive capture | Pick correct mic, unmute, close other apps | Meter moves in WebRTC Test |
| Devices pass but calls connect with no audio/video | Network blocks UDP/STUN/TURN, VPN “block WebRTC” feature | Test on hotspot, adjust VPN settings, involve IT | Connectivity line turns green; call works on hotspot |
| Video works but freezes / green blocks | GPU decode/compositing path unstable | Update GPU driver; test acceleration toggle | Stable preview and stable call |
| App says “codec not supported” | Missing H.264/VP8/VP9 on that browser/OS | Run Codec Test; fix missing codec | Codec Test shows required codec support |
If you don’t know which line matters, run the readiness check: Is My Browser Ready for Video Calls?.
Fix layer 1: Site permission (the most common blocker)
If the browser prompt never appears or you previously clicked “Block”:
- Use the lock icon in the address bar for the meeting site.
- Set Camera and Microphone to Allow.
- Reload the page and re-run the WebRTC Test.
If you’re testing multiple call apps (Meet + Teams + Discord), do this per site. Permission state is stored per origin.
Fix layer 2: OS permission and device selection
Even with browser permission, the OS can block capture.
Checklist:
- Confirm OS privacy toggles allow camera/mic for your browser.
- Pick the intended devices inside the meeting app.
- Unplug unused USB devices to simplify the list.
- Close apps that own devices (Zoom desktop, Teams desktop, Discord desktop, OBS).
Then re-run the WebRTC Test. If the preview and meters are alive, capture is working.
Fix layer 3: Network path (UDP/STUN/TURN and corporate firewalls)
If camera and mic pass but calls fail, the network is the next suspect.
Do this in order:
- Test the same call on a mobile hotspot (fast isolation).
- If it works on hotspot but not on Wi‑Fi, your Wi‑Fi path is blocking real-time traffic.
- If you’re on a VPN, disable any setting labeled “block WebRTC” or “prevent WebRTC leak” and retry.
If you’re on a corporate network, the fix is usually policy-based:
- IT needs to allow the meeting provider’s TURN servers and real-time ports.
- If IT needs proof, send them a screenshot of your WebRTC Test failure plus the fact that hotspot works.
Fix layer 4: Codec compatibility
Some services negotiate a codec your browser can’t decode.
Run the Codec Test and look for:
- H.264 (common in enterprise)
- VP8/VP9 (common in WebRTC)
If a service explicitly mentions H.264 and it’s missing, use the targeted fix guide: Fix H.264 Not Supported.
Fix layer 5: Stability issues (glitchy video, freezes, or flicker)
If the call connects but video is unstable:
- Update GPU drivers first.
- Then test toggling browser hardware acceleration to isolate the path.
- If stability improves with acceleration off, keep it off temporarily and re-enable after a driver update.
Re-run the WebRTC Test and confirm the preview is stable for at least a minute.
Verify the fix (the only part that matters)
When you think it’s fixed:
- Re-run the WebRTC Test until camera + mic + connectivity lines are green.
- Join a real call and confirm two-way audio and video.
- If it fails only on one site but tests look fine, the problem is likely app-side or account-side; try a fresh browser profile and test again.