SAP Message XR303 - Supplier &2 cannot be uniquely assigned to plant

Diagnosis Partner &2 is assigned as supplier to partner &1 in CRM. This functionis represented in SAP R/3 as supplying plant. Partner &2 is assigned tomore than one plant; therefore unique assignment is not possible. System Response The supplying plant function cannot be filled. Procedure Check the assignment of plants to business partners inCustomizing --> Set Up Stock TransportOrder. Only one business partner can be assigned to each plant.