Shipping type preliminary leg/subsequent leg unnecessary

What causes this issue?

You have not specified the shipping type preliminary leg and the
shipping type subsequent leg, although these are necessary in this
case.

System Response

Shipping type VL and shipping type NL are necessary if the following
conditions are to be met at the same time:
-Leg determination type '2' or '3' active
-Leg indicator in the shipment header is set at
'2' (main leg) '4' (direct leg) or '5' (subsequent leg)
See also the F1 Help text on the leg determination indicator.

How to fix this error?

Leave the shipping type preliminary leg and shipping type subsequent
leg fields blank.

Error message extract from SAP system. Copyright SAP SE.