Plan data of version &2/&3 cannot be copied (see long text)

What causes this issue?

You cannot copy planning data from version &V2&, fiscal year &V3& in
controlling area &V1&.

System Response

The system terminates processing.

How to fix this error?

If you still want to copy this data, activate the option "Copying
permitted" under <DS:TRAN.OKEV>Fiscal Year-Dependent Version
Maintenance</> for version &V2&, fiscal year &V3& in controlling area
&V1&.

Error message extract from SAP system. Copyright SAP SE.