The error message you're seeing typically indicates that the SSL certificate provided is not trusted by the Java environment running the Airbyte server. This could be due to a missing or incorrect root certificate, or the certificate chain not being fully trusted. Here are a few steps you can take to troubleshoot this issue: 1. Verify the SSL certificate and key: Ensure that the SSL certificate and key are correctly configured and are located in the specified directories. The certificate should be in the correct format (.pem) and should include the full certificate chain ([source](https://discuss.airbyte.io/t/3370)). 2. Check the logs: Look at the log files for the Airbyte application and the PostgreSQL server for any error messages that might provide more information about the issue. 3. Check the PostgreSQL server configuration: Make sure that the PostgreSQL server is configured to allow SSL connections and that the correct SSL mode is set. The SSL mode should be 'verify-ca' as you have already set ([source](https://docs.airbyte.com/integrations/sources/postgres#step-2-create-a-new-postgres-source-in-airbyte-ui)). 4. Try a different SSL mode: If possible, try using a different SSL mode, such as 'require', to see if the issue is related to the 'verify-ca' mode. Please note that this will only work if your PostgreSQL server supports the 'require' mode and does not require certificate verification ([source](https://docs.airbyte.com/integrations/sources/postgres#ssl-modes)). 5. Check network and firewall settings: Ensure that connections to the PostgreSQL server are not being blocked by any network or firewall settings. If the issue persists, you may need to add the root certificate to the Java keystore of the Airbyte server. This process is not covered in the provided knowledge sources, so you may need to refer to the Java documentation or seek help from the Airbyte community or support.