Hi,
I would recommend that you first check whether the credentials that are passed on to the Oracle with EUS data source are the same as what you are configuring when choosing to use username and password on the data source for authentication.
If this is the same, then you can try adding the oracle related property -Doracle.jdbc.thinLogonCapability=o3 as specified in [Connection to Oracle using Enterprise User Security](https://community.denodo.com/kb/view/document/Connection%20to%20Oracle%20using%20Enterprise%20User%20Security%20%28EUS%29?category=Operation) and test whether it works with passthrough credentials.
Hope this helps!