https://userapps.support.sap.com/sap/support/knowledge/en/2140228
2140228 - Error ME028 "Field selection key &&& not defined" - SAP ERP & SAP S/4HANA | SAP Knowledge...
When creating a purchasing document in transaction ME21N,ME31K,ME51n or change or displaying a purchasing document in transactions ME52N/ME53N, ME22N/ME23N OR...