When I ran a similar Java program that connects to both Oracle and Virtual DataPort server, I was able to connect and query the databases successfully. I made use of the Denodo JDBC driver located at <DENODO_HOME>/tools/client-drivers/jdbc in order to make the connection to Virtual Dataport.
You can check if there are any other configuration changes that are impacting your connection to Oracle databases. You may also verify the credentials to Oracle as the error suggests the credentials are not correct.
If you are still not able to resolve the error and if you are a customer with valid support user, you can raise a support ticket so that Denodo support team can assist you.
Hope this helps!