My Trenitalia ticket for regional transport (ORDINARIA) says "Not valid for travel". What does this mean?

After completing the booking, you will receive a PDF document on which is printed "Not valid for travel", as well as an e-mail containing a booking confirmation from Trenitalia in addition to that issued by DB. The PDF alone does not entitle you to travel.

In the e-mail you receive from Trenitalia, you will find a link to retrieve the barcode for the ticket inspection on the train.

Tickets for the "ORDINARIA" fare are automatically validated at the scheduled departure time of the train you have booked. You can change the date and departure time before the booked day of travel. On the booked day of travel, you can change the departure time before the ticket is automatically validated. Once the ticket has been validated, no more changes can be made. You can also exchange your ticket via the link in the Trenitalia booking confirmation.