Means of transport type & has invalid packaging material type &

What causes this issue?

The <DS:DE.TRATY>means of transport type</> was entered without a
<DS:DE.TRMTYP>means of transport</>. The <DS:DE.VHART>packaging
material type</> found for the means of transport type does not have
any <DS:DE.VELTP>packaging material category</> relevant for the
shipment.

System Response

The means of transport type entered cannot be used.

How to fix this error?

Enter a means of transport type that has a packaging material category
relevant for the shipment.

Error message extract from SAP system. Copyright SAP SE.