Header promotion number &1 is invalid for item &2

What causes this issue?

The header promotion number is invalid. If you have set automatic
promotion determination per sales document type in Customizing, the
system determines the promotion number.

System Response

The header promotion number is not copied to the item.

How to fix this error?

The header promotion number is invalid. Check the following:
promotion material
unit of measure
pricing data of order

Error message extract from SAP system. Copyright SAP SE.