Solution : https://service.sap.com/sap/support/notes/574460 (SAP Service marketplace login required)
Key words :
external document number reason, external purchase order number, function module bapi_po_create1, external number, purchase order, number assignment, terms bapi_po_create1, filled correctly, program error, solution refer
Related Notes :
| 582252 | BAPI_PO_CREATE1/..._CHANGE: Header conditions are incorrect |
| 530900 | BAPI_PO_CREATE1: External PurchOrder number not transferred |