Oracle Message ORA-16757 - unable to get this propertys value

ERRORunable to get this propertys value
CAUSEThe Data Guard broker failed to get the value for the specified property, possibly because the specified propertys value is not available for the current database role.
ACTIONIf the specified propertys value is not available for the databases current role, please specify this property for a database for which it is available. Otherwise, check the Data Guard broker log for more details.