Optimizer run canceled; different direct shipment options currencies used

What causes this issue?

You have not defined a currency for direct shipment options in the
constraints and costs settings. The direct shipment options of the
freight units use different currencies.

System Response

The optimizer run was stopped.

How to fix this error?

Define a currency for direct shipment options in the constraints and
costs settings. During planning, the system converts the different
direct shipment options currencies of the freight units into the
currency that you defined in the constraints and costs settings.
Restart the optimizer run.

The system issues an error message and will not allow you to continue with this transaction until the error is resolved.

Error message extract from SAP system. Copyright SAP SE.