Price &1 has incorrect unit of measurement

What causes this issue?

You have allocated price &v1& to price operand &v2& in the facts. The
unit of measurement &v3& for the operand does not correspond to the
unit of measurement &v4& for the price.

System Response

How to fix this error?

Allocate a price with the unit of measurement &v3& to price operand
&v2& in the facts.

Error message extract from SAP system. Copyright SAP SE.