Gravity Forms confirmation page/text not showing in edge/chrome

Hi Everyone,

I made a Gravity form for customers to download an e-book. However, after submitting the form, there is no confirmation in edge and chrome (every now and then it does work, but I don’t know). It works perfectly in Firefox. I’ve also found another contact form on the website that was there before I started working here and it has the same problem.

Everything is built in the gravity form builder, and with the default confirmation page (no condition). Only a small CSS for the submit button to have a different color (I also removed it to check if something was wrong, it worked in Chrome then, but not in Edge).

Thank you!

The page I need help with: [log in to see the link]