No material group PM maintained for selected materials / packaging matls

What causes this issue?

The <LS>Allowed packaging materials</> function is based on the
"allowed packaging materials" settings in Customizing and only works
for materials or packaging materials whose <DS:DE.MAGRV>Material Group
Packaging Materials</> are maintained.
None of the materials or packaging materials you have chosen has a
material-group packaging-material.

System Response

Materials that have no material-group packaging-materials can be packed
in all <DS:DE.VHILM>packaging materials</>. No Customizing checks are
run.

How to fix this error?

Maintain the material-group packaging-materials in the material master.

Procedure for System Administrators

Maintain the material-group packaging-materials in the
<DS:TRAN.MM02>material master</>.

Error message extract from SAP system. Copyright SAP SE.