No base unit of measure can be determined for the manufacturer part

What causes this issue?

The system has tried to copy the base unit of measure for the
<DS:GLOS.manufacturer_part>manufacturer part</> from your company's own
material. However, no base unit of measure could be determined due to
one of the following reasons:
You have not assigned the manufacturer part to a material of your own.
The material to which the manufacturer part is assigned does not have a
base unit of measure, that is, the material master record is defective.

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?

Depending on the cause, choose one of the following options:
Assign the manufacturer part to a material of your own.
Correct the material master record of the material to which the
manufacturer part is assigned.

Error message extract from SAP system. Copyright SAP SE.