Check net weight

What causes this issue?

The weight unit in the delivery header is valid for the gross weight as
well as the net weight.

System Response

If you make manual changes to the weight unit in delivery change mode
of the overview screens, the net weight is automatically converted to
the new weight unit.
However, if you create an outbound delivery without order reference,
the net weight cannot be converted to the new weight unit if the weight
unit was changed manually. In such a situation, the net weight could be
incorrect. There is no check to make sure the net weight is less than
the gross weight.

How to fix this error?

Check the weights in the details view of the delivery header.

Error message extract from SAP system. Copyright SAP SE.