ERROR: while execution of txkPostPDBCreationTasks.pl ( Part of converting noncdb to pdb ) or any other 19c ebs Database phases:

FUNCTION: main::validateAppsSchemaCredentials [ Level 1 ]
ERRORMSG: Invalid APPS database user credentials.

SOLUTION:
Possible areas and tips to review and fix the above issue :
Make sure :
– Select name from v$active_services
and make sure below services are present and configured:
( ebs_PROD, PROD_ebs_patch, PROD)
-PDB SID in small letters/Capital letters accordingly present in Ebs DB Ctx File.

Make sure below 19c Database Parameters are properly set:
–.local_listener=’hostname.domain:dbport’ in parameter file
–.service_names=ERPCDB
–.db_domain parameter removed from DB parameter file
–.sev_case_sensitive should be false