Configurable material &2 for material &1 not in integration model

What causes this issue?

The material variant &V1& chosen refers to the configurable material
&V2&. Material &V2& is not contained in the integration model.

System Response

This message is a warning. Further processing is not prevented.

How to fix this error?

Include the configurable material &V2& for the selected material
variant &V1& in the integration model.

Error message extract from SAP system. Copyright SAP SE.