BigBlueButton – Troubleshooting

This guide helps with common BigBlueButton issues – including technical notes for IT departments.

❌ Connection not possible (meeting does not load / disconnects)

For users (quick check)

  • Reload the page (F5 / Reload)
  • A modern browser should be installed: Chrome, Firefox, Edge, or Safari – or a browser based on Chrome (which applies to most browsers).
  • Disable VPN, if active
  • Try a different network (e.g. mobile hotspot)

Note: In corporate or government networks, firewalls or proxies may block real-time communication (WebRTC). In this case, please contact your IT department.

For IT / network administration (technical requirements)

Required outbound connections:

  • TCP 80 / 443 – HTTP/HTTPS (service access)
  • UDP 16384–32768 – audio/video (WebRTC media streams)

Additionally required for NAT / restrictive firewalls:

  • UDP & TCP 3478 – TURN/STUN (for connections behind NAT/firewalls)

Important: Firewalls or proxies must not block WebSocket or WebRTC (no WebRTC blocking, no aggressive inspection or proxy interception).

Allowed server IP addresses (allowlist):

think-modular.com

  • 88.99.139.48/32
  • 49.12.147.4/32
  • 195.201.86.154/32
  • 116.203.225.96/32

bbb-connect.com

  • 188.40.71.172/32
  • 188.40.75.228/32
  • 88.198.26.157/32

🔇 No sound / no video (microphone or camera not working)

For users

  • Check permissions: allow camera & microphone in the browser (lock icon next to the address bar)
  • Select the correct device (in BigBlueButton: microphone, camera, speakers)
  • Close other applications (Teams, Zoom, Skype, etc. may block camera/microphone)
  • Check your internet connection: stable connection preferred, ideally wired (LAN) instead of Wi-Fi

Technical note

  • For audio/video, UDP ports 16384–32768 must be reachable.
  • In restrictive networks, TURN/STUN via port 3478 is essential.

🐌 Delays / stuttering / poor audio quality

For users

  • Check internet speed and switch to a different network if necessary
  • Pause downloads/streaming and close unnecessary browser tabs
  • In BigBlueButton, under “Data savings”, try disabling:
    • “Enable other participants webcams”
    • “Enable other participants desktop sharing”

For IT / network teams

  • High latency, packet loss, or insufficient upload bandwidth can cause poor audio/video quality.
  • Proxy inspection, DPI, or UDP blocking can severely interfere with WebRTC.

🧪 Tests

For users

Test camera and microphone independently of BigBlueButton:

WebRTC Audio/Video Test (external)

If it does not work there, the issue is very likely related to the browser, device, or network – not BigBlueButton itself.

For IT (quick connectivity test)

Please run these tests from a client within the affected network:

HTTPS reachability test
nc -vz bbb.think-modular.com 443

UDP connectivity test (TURN server)
nc -vu bbb-01.think-modular.com 3478 

🆘 If problems persist

Please send the following information to support or IT:

  • Browser and version
  • Network (corporate/home office, VPN yes/no)
  • Error message (screenshot if possible)
  • Note: “BigBlueButton requires WebRTC and open UDP ports (16384–32768), and may require TURN/STUN via port 3478.”