https://userapps.support.sap.com/sap/support/knowledge/en/3279826
3279826 - Error MEPO 301 raised during Purchase Order creation in ME21N - SAP ERP & SAP S/4 HANA. |...
When trying to create a Purchase Order in ME21n from a Purchase Requisition or Request for Quotation, the error 'Purchase requisition ********* is in external...