Yes. For security,
KSÍ may program the tickets so that the QR code only appears a certain time before the match (for example, 4–24 hours prior).
Before that time window, you will see a blank or “inactive” ticket.
This prevents potential misuse.
On match day, when you click the ticket in the app, the QR code should be visible.
If you are in the stadium and still don’t see it, ensure you have a working internet connection or try restarting the app.