Postgre SDL Databes automatic refresh - Manage Gateway

I have a Postgre SQL database in AWS. I am trying to automatize the refresh process to do it automatically once per day. I have downloaded and connected the Data Gateway. I have downloaded and installed Baltimore Certificate in my Computer. Then I go to settings and Manage gateways and add a New Data Source.

I complete all the Data Source Setting (Data Source Name, Data Source Type, Server, Database, Username, Password and Advance Settings as None). Also I have completed the data related to users.

When I click “Apply” I receive the following error related to a not valid remote certificate following the validation process.