A 401 error in Databricks typically indicates an authorization issue, meaning the system cannot verify the user’s identity or the provided credentials are invalid. Here are the common causes and solutions:

Common Causes:

1. Incorrect Personal Access Token (PAT): Ensure the PAT you’re using is valid, active, and has the necessary permissions to perform the requested action. Generate a new PAT if needed.
2. Expired or Revoked Token: If you’re using an OAuth token, it might have expired or been revoked. Renew the token or obtain a new one.
3. Insufficient Permissions: The user or service principal you’re using might need the required permissions to access the Databricks resource. Check the permissions and grant the necessary access.
4. Incorrect Cluster Configuration: If you’re using a shared cluster with “No Isolation” mode, you might be unable to access secrets due to security restrictions. Switch to a different cluster mode or configure the cluster appropriately.
5. Network Issues: A network problem could prevent the system from verifying your credentials. Check your network connection and ensure you can reach the Databricks endpoint.

Solutions:

1. Verify Your Credentials: Double-check your PAT, OAuth token, or other authentication method to ensure it’s correct and valid.
2. Check Permissions: Review the permissions of the user or service principal you’re using and ensure they have access to the Databricks resource.
3. Configure Cluster Settings: If you’re using a shared cluster, switch to a different cluster mode or configure the cluster to allow access to secrets.
4. Troubleshoot Network Issues: Check your network connection and ensure you can reach the Databricks endpoint. If you’re behind a firewall, ensure it’s not blocking access to Databricks.
5. Consult Databricks Documentation: Refer to the Databricks documentation for troubleshooting steps and standard solutions for 401 errors.
6. Contact Databricks Support: If you still can’t resolve the issue, contact Databricks support for further assistance.