Account & requires an assignment to a CO object

What causes this issue?

You have not defined a CO account assignment for an account that is
relevant to cost accounting.

System Response

Account &V1& is defined as a cost element.
This means that you must always specify a CO account assignment.

How to fix this error?

Enter one of the following CO account assignments:
INCLUDE 'CO_KONTIERUNGEN' OBJECT DOKU ID TX
The posting row affected is &V2&, account &V1&.

Error message extract from SAP system. Copyright SAP SE.