Oracle Solution for Error ora-16621

ORA-16621: database name for ADD DATABASE must be unique

What triggered the Error:

An attempt was made to add a database to the broker configuration that already included a database with the specified name. The database names must be unique.

What should we do to fix it:

Verify that a unique name is specified for the new database to be added. Also, the database name must match the DB_UNIQUE_NAME initialization parameter of the database.