Redirectin to new page

We have redirect with this guide ( https://contactform7.com/redirecting-to-another-url-after-submissions/ ) to another page after filling the form. There is an issue in the loading. Because of the redirect the spinner isnt shown and it looks like the page isnt doing nothing after submission and the load takes time to direct to thank you-page. And the issue is that the person who filled the form doesnt necessary have patience to wait the thank you page.

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