An error occurred in prepayment

What causes this issue?

An error occurred in the prepayment during verification of this invoice
in the background.
For example, there may be delivery notes assigned to the invoice that
refer to purchase orders with fixed exchange rates. However, the fixed
exchange rate was not entered in the invoice header initially and is the
refore not used in the prepayment.

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?

Go to the details screen for this invoice (in transaction <LB>MIR6</>).
If you try to select the invoice or schedule it again for invoice
verification in the background, you receive an error message with the
cause.

Procedure for System Administrators

Error message extract from SAP system. Copyright SAP SE.