Revision history [back]

There could be several reasons why you are unable to establish a connection with MongoDB. Some common causes and possible solutions are:

1. Incorrect server address or port: Make sure that you are connecting to the correct server address and port number. Check your connection string and verify that it contains the correct values.

2. Authentication failure: If you have enabled authentication on your MongoDB instance, make sure that you are providing valid credentials. Check that the username and password are correct and that the user has the necessary permissions to access the database.

3. Firewall blockage: Check that your firewall is not blocking the connection to MongoDB. Verify that your network settings allow communication with the MongoDB server.

4. MongoDB service not running: Make sure that the MongoDB service is running on the server. If not, start the service and attempt to connect again.

5. Driver version mismatch: Verify that you are using the correct version of the MongoDB driver for your version of MongoDB. Check the documentation for compatibility information.

6. Connection pool configuration: Check that your connection pool configuration is set up correctly. Make sure that you are not exceeding the maximum connection limit for your MongoDB instance.

If you are still unable to establish a connection after trying these solutions, consult the MongoDB documentation or reach out to their support team for further assistance.