Acknowledgment for PO item & & contains quantity variance

What causes this issue?

The supplier has sent you an order acknowledgment relating to purchase
order &V1&, item &V2&, via EDI. The acknowledged (confirmed) quantities
exceed the under-/overdelivery tolerances that have been maintained in
the PO item and have therefore not been adopted in the purchase order.
The total quantity confirmed amounts to &V3& <unit of measure> in
comparison with the ordered quantity of &V4& <unit of measure>.

How to fix this error?

Either change the over/underdelivery tolerances in the PO item

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

<DS:TRAN.ME22N>Change purchase order</>
Or get the supplier to send you a new acknowledgement with acceptable
quantities.

Error message extract from SAP system. Copyright SAP SE.