Coefficient and fixed density/gravity only allowed for chemicals

What causes this issue?

You attempted to enter a thermal expansion coefficient (quantity
conversion coefficient) and/or a fixed density for a material that has
been assigned to a non-chemical conversion group.

System Response

The system issues an error message and will not allow you to continue with this transaction until the error is resolved.

How to fix this error?

Change the conversion group of the material to a chemical conversion
group (234C, 534C or 56C) or leave the entries blank. Removing the
conversion group is only possible if no stock has been posted yet.

Error message extract from SAP system. Copyright SAP SE.