Oracle Message ORA-16799 - Redo Apply is not running

ERRORRedo Apply is not running
CAUSEEither the Data Guard broker metadata indicates that Redo Apply was turned off, or the recovery process, MRP0, was not running. As a result, Redo Apply-related properties could not be set.
ACTIONTurn on Redo Apply through Data Guard broker and reissue the command to set a Redo Apply-related property.