Release:11.2, 12.0, 12.1, 12.2, 12.3
Component: Automation Engine
If you want to test the Connection Object, do not use the Test button inside the CONN object itself: This button uses the DB Service for the testing which doesn't have the necessary elements.
Instead, create a test job that uses the Connection Object, then run the job or use the Test button inside job for testing the connection.