Value exceeds limit & & in PO

What causes this issue?

You are entering an invoice for a blanket purchase order. The value you
entered leads to the maximum amount of &V1& &V2& being exceeded.
&V3& &V2& has already been committed.
INCLUDE MM_IV_MELDUNGEN OBJECT DOKU ID TX

System Response

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

How to fix this error?

Check the amount invoiced. If the amount is correct, the Purchasing
department has to change the purchase order and increase the maximum
amount.

Error message extract from SAP system. Copyright SAP SE.