Select the future main EAN for unit of measure &

What causes this issue?

You have deleted the main EAN (International Article Number) for the
current unit of measure. However, additional EANs still exist for this
unit.

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?

Select one of the additional units of measure as the future main EAN.

Error message extract from SAP system. Copyright SAP SE.