Message type: E = Error
Message class:  APPL_MM_PUR_DAAG - Data Aging Message Class 
Message number: 028
Message text: Invoiced quantity not the same as GR quantity for &1 &2
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The SAP error message APPL_MM_PUR_DAAG028 indicates that there is a discrepancy between the invoiced quantity and the goods receipt (GR) quantity for a specific purchase order item. This error typically arises during the invoice verification process in the Materials Management (MM) module when the system detects that the quantity on the invoice does not match the quantity that was received.
Cause: Quantity Mismatch: The most common cause is that the quantity invoiced by the vendor does not match the quantity that was recorded in the goods receipt. This can happen if: The vendor sent a different quantity than what was received. There was an error in entering the quantities during the goods receipt or invoice entry. Partial deliveries were made, and the invoice reflects a different quantity than what was received. Invoice Entry Errors: Manual entry errors during the invoice creation process can lead to discrepancies. Goods Receipt Not Posted: If the goods receipt was not posted
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