ORA-16757: unable to get this property's value

admin

ORA-16757: unable toget this property's value
Cause: The Data Guard broker failed to get the value for thespecified property,
possibly because the specified property's value is not available for thecurrent
database role.
Action: Ifthe specified property's value is not available for the database's current
role, please specify this property for a database for which it is available.
Otherwise, check the Data Guard broker log for more details.