Transport calendar &1 does not exist

What causes this issue?

The transportation calendar &V1& that you have specified in the
transportation lane &V2& does not exist.

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?

Check the existing transportation calendar.
If necessary, maintain a calendar in Customizing in SAP Advanced
Planner and Optimizer (SAP APO) under <ZK> Master Data -> Calendar ->
Maintain Planning Calendar (Time Stream)</>.

Procedure for System Administrators

Error message extract from SAP system. Copyright SAP SE.