By default, the reason is that the booking process has not been completely finished. After you have confirmed the payment in the TWINT app, you have to go back to the SportsNow app and press «Complete booking». In the browser, you will be automatically redirected. Only then the booking is definitely confirmed.
There may occur problems when trying to pay with TWINT in the browser on your smartphone, as you have to switch back and forth between the browser and the app. For a seamless payment process, we therefore recommend to use directly the SportsNow app.
If booking/paying still doesn't work out, try again at a later time if necessary or contact your studio so they can sign you up.