Mobile payment problem

Hello, I use the Bancontact payment method (a Belgian payment method), when I want to pay everything opens correctly but on mobile, we can directly open its banking application. From the application, when you click on the button to open the banking application, nothing happens and you have to pay with an electronic box, a big waste of time.

I do not think that the problem comes from the means of payment, the problem is that my application cannot open other applications

my website it’s https://www.bio-et-locaux.be