Hello, @Ferry,
I see, So now I have tested your site on real iPhone mobile and it is still working fine for me, please watch these videos I have captured for you.
https://www.veed.io/view/e717968f-02f1-4336-a7da-854ec7ec94b1?sharingWidget=true
https://www.veed.io/view/05eaa1f8-abeb-4d66-ac20-945009137330?sharingWidget=true
It may be an Ajax server error when you made a test, please try to clear the cache and check back again.
Regards 8Themes Team.
