ORA-12514: TNS:listener does not currently know of service requested in connect descriptor after cluster upgrade to 19c

Problem

users get error while connecting to database

ORA-12514: TNS:listener does not currently know of service requested in connect descriptor

Cause:

Cluster upgrade from 12.2 to 19c

Solution:

set remote_listener parameter

alter system set remote_listener=’racscan.com:1521′ scope=both sid=’*’;