Dropdown for category select

-- url of the page with the problem -- : www.trichi.it
-- HikaShop version -- : 4.1.0
-- Joomla version -- : 3.9.8
-- PHP version -- : 7.0
-- Browser(s) name and version -- : chrome

when I insert a product I don't have anymore the dropdown to select the category, I updated hikashop and joomla but I still have the problem and all the new product are categorized on the root (product category) and also if I write the category when I save the products they only save the 'product category' category-

Hi,

You can try clicking the "rebuild" button of the Products>Categories listing. That might help fix the issue.
Otherwise, I'm afraid we'll have to directly look at the situation on your website.
In that case, please provide a backend access along with a link to this thread via our contact form:
www.hikashop.com/support/contact-us.html