Problem: I get an error (red dot) when I try to process the invoice (MIRO).

Solution: Typical errors include the following:

1. You did not yet process the goods receipt; therefore you cannot yet process the invoice.  You can verify this by running both ME2M, where you will see that there is still a quantity to receive; and also MD04, where you will see the PO is still open.  Remember that when you receive the goods into stock, the PO will no longer be visible (it will be closed), and your stock quantity will be incremented by the PO quantity.  Look at these transactions to be sure that you understand… and THEN, run the goods receipt transaction.
2. You already processed the invoice, and cannot process it (pay the vendor) a second time.  You can verify this using transaction ME2M, the same as described above.  If you already processed the invoice, you will see “zero” for “still to be invoiced”
3. You will need to be sure that you received the goods into stock before you process the invoice.  You can verify that you ran the goods receipt by either 1) run ME2M for your material, and view your PO#.  If you already received the goods into stock, it will show a balance of zero to receive into stock.  OR 2) run MD04 and look for your PO number.  If your PO number is visible with the full quantity, then you did not process the goods receipt.  If you successfully processed the goods receipt, the PO would not be visible on MD0 and the stock quantity would be incremented by one.