Cancel settlement for period & & first

What causes this issue?

In period &v1& &v2&, actual costs were settled to the receivers of the
settlement rule. However, the sender is a WIP element, which means:
The sender is an order or a WBS element.
The sender has a results analysis key.
You cannot post revenues to the sender.
A WIP element is treated according to the following rules:
If the sender is not technically completed or has not been finally
delivered, then only work in process is transferred to Financial
Accounting.
If the sender is technically completed or has been finally delivered,
then the system settles the actual costs for the sender to the
receivers, as specified in the settlement rule.
If you reopen the sender or reset the final delivery after the actual
costs are settled, then you need to reverse this settlement.

How to fix this error?

Reverse the settlement of actual costs, as the sender is not
technically completed, and has not been finally delivered.
If you do not wish to determine WIP on your order or WBS element, then
you can cancel the results analysis key after reversing the settlement.

Error message extract from SAP system. Copyright SAP SE.