12c SOA Weblogic console - Database - shared memory realm does not exist IBM AIX RISC System/6000 Error: 2: No such file or directory error

While one of the SOA external DB was upgrading to 19c, I have stumbled with this following error during the datasourse connection testing.

Test of WorkboothDB on server osb_server1 failed, reason:

Error Connection test failed with the following exception: weblogic.common.resourcepool.ResourceDeadException: 0:weblogic.common.ResourceException: ORA-01034: ORACLE not available ORA-27101: shared memory realm does not exist IBM AIX RISC System/6000 Error: 2: No such file or directory

Solution:

This is because the Database instance name got changed. I have used the correct instance name and it got resolved.