Scheduling is deactivated

What causes this issue?

You are using the transportation planning and shipment scheduling
simulation. However, scheduling cannot be executed because you have
neither activated transportation planning nor shipment scheduling
for the item to be scheduled.

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.