Quantity structure not found for co-product & in plant &

What causes this issue?

For material &V1& in plant &V2&, the co-product indicator is set in the
material master. However, no BOM could be found for this material, or
process in which the co-product appears as an output material.

System Response

A material price is used to cost the material.

How to fix this error?

Check the material master data.

Error message extract from SAP system. Copyright SAP SE.