Settlement with net document type not possible

Used exclusively in repnort RMVKON00 (consignment settlement)

What causes this issue?

IF &V1& = 'MRKO'.
For the settlement of consignment withdrawals
ELSE
For the settlement of pipeline withdrawals
ENDIF.
net document type &V2& has been defined. Net posting has not, however,
been defined for this type of settlement.

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?

Your system administrator must either
define &V2& as a gross document type or
enter another document type for transaction &V1&.
<DS:TRAN.OMR4>Proceed</>

Error message extract from SAP system. Copyright SAP SE.