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Troubleshooting: Data Connection Issues

Connection test fails​

Probable causes:

  • Incorrect credentials (URL, token, username, password).
  • The server is unreachable from Crow's Nest (firewall, network issue).
  • SSL mismatch (SSL enabled in config but not on the server, or vice versa).

What to do:

  1. Double-check all credential fields in the data source config.
  2. For SQL databases, verify the server allows connections from external IPs. Crow's Nest connects from Cloudflare Workers.
  3. For MQTT, confirm the broker URL starts with ws:// or wss:// (WebSocket protocol required).
  4. Try toggling the SSL setting if available.

getData() returns empty results​

Probable causes:

  • The source table or query has no matching records.
  • Filters on the data connection are too restrictive.
  • Caching is stale (Tulip connections).

What to do:

  1. Check the data connection's filter configuration. Remove filters temporarily to test.
  2. For Tulip connections with caching enabled, the cache may not have refreshed yet. Wait for the next delta refresh interval, or disable caching temporarily.
  3. For SQL connections, run the query directly in your database tool to verify it returns results.

Cache not refreshing (Tulip connections)​

Probable causes:

  • The delta refresh or full rebuild interval hasn't elapsed yet.
  • The cache was corrupted during a write and is rebuilding.

What to do:

  1. Check the cache settings on the data connection. The default delta refresh is 5 minutes.
  2. If the cache seems stuck, edit the connection and save it again to trigger a rebuild.
  3. As a workaround, temporarily disable caching to fetch fresh data.

MQTT not receiving messages​

Probable causes:

  • The topic name doesn't match what the broker is publishing.
  • QoS settings are preventing delivery.
  • The broker connection dropped.

What to do:

  1. Verify the topic exactly matches the publisher's topic (topics are case-sensitive).
  2. Try QoS 1 instead of QoS 0 for more reliable delivery.
  3. Test the broker and topic with a separate MQTT client to confirm messages are flowing.
  4. Check the data source config credentials and test the connection.

"Config not accessible" error​

Cause: Your user account doesn't have access to the data source config this connection uses.

What to do: Ask your admin to grant you access to the relevant config.

Connection disappeared from the list​

Probable causes:

  • The data source config it referenced was deleted.
  • Your config access was revoked.

What to do:

  1. Check with your admin whether the config still exists.
  2. If your access was revoked, ask to have it restored in Organization Settings.