Invoice reference to cleared item

What causes this issue?

The specified line item has already been cleared or is included in a
payment order. In both of these cases, it is no longer possible to
settle the invoice and the assigned credit memo at the same time in this
system.

System Response

Warning drawing your attention to the status of the invoice item.

How to fix this error?

The system creates the invoice reference; the line item is marked in
such a way that the due date is determined as for the invoice.
If you want to refer to another invoice line item, enter the required
document number in the invoice reference field and enter the line item
number and fiscal year as necessary.
INCLUDE 'CUSTOMIZED_MESSAGE_INFO' OBJECT DOKU ID TX

Error message extract from SAP system. Copyright SAP SE.