It may occur that a warning message pops up during PO line entry, that Item/supplier does not exist.

PPS095/F: some PO types, such as INV, require a valid record in PPS040, where the connection between an item and supplier can be created. 

See setting 110 – mandatory item/supplier record is selected for PO type INV.

In that case a record in status 20 in PPS040 is required.