SAP Message XR301 - Supplier &2 cannot be assigned to a plant

Diagnosis Partner &2 is assigned as supplier to partner &1 in CRM. In R/3, thisfunction is represented as supplying plant. However, no plant to whichpartner &2 is assigned could be determined. System Response The supplying plant function cannot be filled. Procedure Check the assignment of plants to business partners inCustomizing --> Set Up Stock Transport Order.