Prepayment not possible in combination with down payment clearings

What causes this issue?

Down payment clearings have been posted for the parked invoice.
At the same time, this invoice is to be prepaid.

System Response

The invoice document cannot be saved.

How to fix this error?

Delete either the down payment clearings or the prepaid status.

Procedure for System Administrators

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

Error message extract from SAP system. Copyright SAP SE.