GuidesConnecting
Troubleshooting connections
Common connection issues and how to resolve them.
Common issues
Connection refused
| Cause | Solution |
|---|---|
| Wrong endpoint | Use mqtts://mqtt.cloudsignal.app:8883 (native clients) or wss://connect.cloudsignal.app:18885/ (browser clients) |
| Wrong broker URL | Use mqtt.cloudsignal.app |
| Invalid credentials | Check username format is username@org_short_id |
| Protocol version blocked | Check Settings → MQTT for allowed protocol versions |
Authentication failed
Check the Logs → Errors tab in your dashboard to see the specific failure reason.
| Error | What to check |
|---|---|
| Invalid credentials | Verify the password matches what was set in the dashboard |
| Username format | Username must include the @org_short_id suffix |
| Protocol version not allowed | Your organization has restricted certain MQTT versions in Settings → MQTT |
Connection drops
| Cause | Fix |
|---|---|
| Clean session | If clean_session=true, the broker won't keep session state between reconnects |
| Keep-alive timeout | Set a keep-alive interval (recommended: 60 seconds) |
| Network issues | Check that your client's reconnection logic handles transient failures |
ACL denied
If you can connect but can't publish or subscribe:
- Check Logs → Errors for ACL denial entries.
- Review your ACL rules in Dashboard → Access Control.
- Without custom ACL rules, users have access to all topics by default.
- Once you add any ACL rule, only explicitly allowed access is permitted.