Line ID &2 does not exist in controlling area &1

What causes this issue?

You entered a line ID that you have not yet defined.

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 into Customizing for Product Cost Controlling and carry out the step
"Define Line IDs". Then perform the activity again.

Error message extract from SAP system. Copyright SAP SE.