This appears to be a Oracle error code that Tableau is directly sharing. You will need to work with Oracle to determine why the duplicate listner is happening
Also, please be sure to review the KB article for Oracle troubleshooting.
I hope that helps
You might have to fix it at Oracle level
ORA-12542: TNS:address already in use
Cause: Specified listener address is already being used.
Action: Start your listener with a unique address.
Try to isolate the issue by connecting with some other tool like TOAD so that you are assured of the same.
If it is not connecting with TOAD as well then it is not related to Tableau.(most probably it is not related )
Please mark the relevant answer(s) if it helps you