Oracle Message ORA-23340 - incorrect resolution method string

ERRORincorrect resolution method string
CAUSEUser function is specified when conflict resolution method was not USER FUNCTION or specified resolution method is not one of the predefined methods.
ACTIONIf user function is specified when conflict resolution method was not USER FUNCTION, either reregister function with method as USER FUNCTION or specify a NULL user function. Otherwise Specify one of the documented supported conflict resolution methods.