EBS 12.2: Autoconfig/Sqlplus connection is faling with ORA-28547 on 19c

Issue: 

Receiving   "ORA-28547: connection to server failed, probable Oracle Net admin error"  while running autoconfig (or) connecting via sqlplus  after sourcing CDB (or) PDB env file.

Cause:

Missing $ORACLE_HOME/nls/data/9idata directory

Solution:

 

On the database server node, as the owner of the Oracle RDBMS file system and database instance, run the following command to create the $ORACLE_HOME/nls/data/9idata directory.

$ perl $ORACLE_HOME/nls/data/old/cr9idata.pl

After creating the directory, make sure that the ORA_NLS10 environment variable is set to the full path of the 9idata directory whenever you enable the 19c Oracle home.

Now re-run the autoconfig & make sure it completes without any issues.