Error: Unable To Access Change Streams / Oplog

Issue

The connection fails. The following error appears:

Unable to access Change streams / Oplog. Setup test failed with "com.fivetran.integrations.mongo.exceptions.MongoConnectionException: Invalid port [mongodb://:27017/]. Detailed error: java.net.ConnectException: Connection refused"

Environment

• Connector: MongoDB
• Connection method: SSH tunnel

Resolution

To resolve this issue, do the following:

1. Identify the internal network address of the MongoDB server that the SSH tunnel host can access.
2. In Fivetran, go to your MongoDB connection page.
3. Select the Setup tab.
4. Click Edit connection.
5. In the Host and ports field, enter the internal address from step 1.
6. Click Save & Test.

Cause

This issue occurs when we can't connect to the MongoDB instance on port 27017. It typically happens when the Host and ports value is set to the SSH tunnel host’s IP address, even though MongoDB is running on a separate node. The field must point to the MongoDB server’s address as reachable from the SSH tunnel host.