No active purchase order item for shipment cost item &1 &2

What causes this issue?

A shipment cost item is to be released for settlement.
The system tried determine a suitable purchase order item for
forwarding.
No active purchase order item could be determined.
A suitable purchase order item was determined, but it is blocked or
deleted.

System Response

The shipment cost item can not be released.

How to fix this error?

INCLUDE SCD_PURCHASE_ORDER_NOT_FOUND OBJECT DOKU ID TX

Error message extract from SAP system. Copyright SAP SE.