Classification key EK not defined for shareholder equity

What causes this issue?

The assignment classsification key EK used in version &V1& for the
stockholders' equity totals item is missing.
This setting is needed for disclosing the notes on the total
stockholders' equity of the internal trading partners in the ownership
list.

System Response

Termination

How to fix this error?

Define this classification key in the Implementation Guide in the
chapter concerning selected items.
IF &DEVICE& = 'SCREEN'
<DS:TRAN.OC04>Proceed</>
ENDIF

Error message extract from SAP system. Copyright SAP SE.