PO item &1 fulfilled, invoice quantity higher than quantity delivered

What causes this issue?

You want to reject a sales order item with individual procurement. The
associated purchase order item &V1& is fulfilled and there is no sales
order stock.
INCLUDE VA_REJ_MSG_INVOICE_QTY OBJECT DOKU ID TX

System Response

INCLUDE VA_CONFIG_MSG_SYSTEMRESPONSE OBJECT DOKU ID TX

How to fix this error?

Check whether the supplier invoices for the purchase order item are
correct. Cancel any invoices that are incorrect.
If this message is configured as an error message and the quantity of
correct invoices is higher than the quantity delivered, you first have
to receive the outstanding goods. It may still be the case that a
rejection is not possible as checks may still be taking place for
existing sales order stock (this is the case after goods receipt).

Procedure for System Administrators

The system issues an error message and will not allow you to continue with this transaction until the error is resolved.

Error message extract from SAP system. Copyright SAP SE.