Cannot send production campaign

What causes this issue?

No location could be determined for at least one order in the
production campaign. Since this is required to send the campaign to an
external system, it was saved but not exported.

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?

Procedure for System Administrators

Error message extract from SAP system. Copyright SAP SE.