I received an error '0K2 Line LPCO Type: The Document Type is missing or invalid fr this PGA program' what does it mean?

Missing information for LPCO. User needs to put the LPCO details/ the description for this transaction if steel and it was under GAC, they just need to put the information on the following:

INVOICE > ITEMS > LPCO

******* GIP20- Steel ******check GIP based on HS code on this website: https://www.international.gc.ca/controls-controles/report-rapports/list_liste/handbook-manuel/contents_contenu.aspx?lang=