---
title: "Live VLM WebUI — Troubleshooting"
canonical: "https://build.nvidia.com/playbooks/live-vlm-webui/troubleshooting.md"
---

| Symptom | Cause | Fix |
|---------|-------|-----|
| pip install shows "error: externally-managed-environment" | Ubuntu protects the system Python environment according to PEP 668 | Install the application in an isolated environment with `pipx install live-vlm-webui` as shown in Step 2 |
| Browser shows "Your connection is not private" warning | Application uses self-signed SSL certificate | Click "Advanced" → "Proceed to \<IP\> (unsafe)" - this is safe and expected behavior |
| Camera not accessible or "Permission Denied" | Browser requires HTTPS for webcam access | Ensure you're using `https://` (not `http://`). Accept self-signed certificate warning and grant camera permissions when prompted |
| "Failed to connect to VLM" or "Connection refused" | Ollama or VLM backend not running | Verify Ollama is running with `curl http://localhost:11434/v1/models`. If not running, start with `sudo systemctl start ollama` |
| VLM responses are very slow (>5 seconds per frame) | Model too large for available VRAM or incorrect configuration | Try a smaller model (`gemma3:4b` instead of larger models). Increase Frame Processing Interval to 60+ frames. Reduce Max Tokens to 100-200 |
| GPU stats show "N/A" for all metrics | NVML not available or GPU driver issues | Verify GPU access with `nvidia-smi`. Ensure NVIDIA drivers are properly installed |
| "No models available" in model dropdown | API endpoint incorrect or models not downloaded | Verify API endpoint is `http://localhost:11434/v1` for Ollama. Download models with `ollama pull gemma3:4b` |
| Server fails to start with "port already in use" | Port 8090 already occupied by another service | Stop the conflicting service or use `--port` flag to specify a different port: `live-vlm-webui --port 8091` |
| Cannot access from remote browser on network | Firewall blocking port 8090 or wrong IP address | Verify firewall allows port 8090: `sudo ufw allow 8090`. Use correct IP from `hostname -I` command |
| Video stream is laggy or frozen | Network issues or browser performance | Use Chrome or Edge browser. Access from a separate PC on the network rather than locally. Check network bandwidth |
| Analysis results in unexpected language | Model supports multilingual and detected language in prompt | Explicitly specify output language in prompt: "Answer in English: describe what you see" |
| pipx install fails with dependency errors | The existing pipx environment may be incomplete or outdated | Recreate the isolated environment with `pipx uninstall live-vlm-webui && pipx install live-vlm-webui` |
| Command `live-vlm-webui` not found after install | The pipx application directory is not in PATH | Run `pipx ensurepath`, then start a new terminal or run `source ~/.bashrc` |
| Camera works but no VLM analysis results appear, browser shows InvalidStateError | Accessing via SSH port forwarding from remote machine | WebRTC requires direct network connectivity and doesn't work through SSH tunnels (SSH only forwards TCP, WebRTC needs UDP). **Solution 1**: Access the web UI directly from a browser on the same network as the server. **Solution 2**: Use the server machine's browser directly. **Solution 3**: Use X11 forwarding (`ssh -X`) to display the browser remotely |