Unit of measure was changed for material &1

What causes this issue?

The base unit of measure for a material- or packaging material item was
changed in the material master.

System Response

In <ZK>Change Packing Instruction</> mode: All quantity fields are
initialized. The system asks you to enter new quantities.
In <ZK>Display Packing Instruction</> mode: The transaction for
displaying packing instructions is canceled.

How to fix this error?

In change mode, enter new values for target quantity, minimum quantity,
and rounding quantity.

Error message extract from SAP system. Copyright SAP SE.