Oracle Error Message
ORA-16642: DB_UNIQUE_NAME mismatch
Reason for the Error
The expected DB_UNIQUE_NAME value did not match the actual DB_UNIQUE_NAME value for the database that the broker contacted using the connect identifier that was associated with that database.
Solution
Verify that the connect identifier correctly connects to the intended database. Verify that the name of the database the broker expects to find by that connect identifier matches the actual DB_UNIQUE_NAME for that database.