Hi, I used the same credential for Desktop 2018.2.0 and Prep 2018.2.3.
The connection worked on Desktop but not Prep.
I made sure Prep driver was installed (instead of Desktop driver), restarted the machine, but still not working.
I also tried the port based on this page. (https://kb.tableau.com/articles/issue/troubleshooting-oracle-connection-errors#listener2 )
Here is the error message I got.
An error occurred while communicating with Oracle.
Detailed Error Message
Oracle database error 12541: ORA-12541: TNS:no listener
Unable to connect to the server "xxxx". Check that the server is running and that you have access privileges to the requested database.
Thank you for any input!
I figured out why and came back to answer my own question. The connection now works with the port number specified in tnsnmaes.ora file.