SAP Message XCB000 - Only one billing order can exist for an inst. ith outline contract

Diagnosis A billing order already exists for the installation with the scheduledbilling date &v1&. System Response There can only be one billing order for the installation with theoutline contract. Procedure Billl the existing billing order in the outline contract or delete thecontract. When you delete the order, make sure there are no billingorders in the system for the allocated installations.