Costs not completely calculated for WBS element & -> see log

What causes this issue?

Costs could not be calculated completely for WBS element &V1&.

How to fix this error?

You can get an overview of errors in the log for cost calculation.
Select the menu options <LS> Extras - > Log -> Cost log-(actvty)</>.

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.