Message SAP WSTRN051 - MAP planning step &2 contains no quantity key figure

Diagnosis MAP planning step &V2& forplanning scenario &V1& does not contain a quantitykey figure (QUANTITY). Procedure It is required to map the generic planning key figure (QUANTITY) to any real quantity key figures, such as, ReceiptsQuantity in Base Unit of Measure (ZUGMNG). Review Customizing for the MAP request ( Maintain Interface for External Applications)or modify your merchandise and assortment planning.