Tickets can be viewed in advance. If you tap on "Show ticket” and it says "No ticket for this day”, then select another date at the top of the screen.

By default, the app will (try to) show the ticket for the current date.

Also see:

https://eurail.zendesk.com/hc/en-001/articles/7544877721245-I-cannot-generate-my-ticket-QR-code-No-ticket-for-this-day-error-message

The advice from the experienced travellers in the Community is to never activate a travel day until just before boarding the first train of the day. If you activate a travel day in advance and your plans change you can’t deactivate the travel day on the same day.

Hi again @rvdborgt i really appreciate your help. So when I do that there is no provision on the screen to change the date - see photo having clicked the three dots 

First tap on Show ticket, then change the date if you see "No ticket for this date”.