AJAX add to cart redirects to checkout

-- url of the page with the problem -- : 222publications.com/en
-- HikaShop version -- : 3.2.1
-- Joomla version -- : 3.8.2
-- PHP version -- : 5.6.32
-- Browser(s) name and version -- : CHROME

Hello,

I've upgraded HikaShop on my website and set the add to cart to the new ajax method.

Now, when a user adds a product to the cart, they'll be redirected to the checkout page.

What's wrong? How can I fix this?

Please help as this is urgent.

Regards,
Simon