Problem with PayPal checkout

-- url of the page with the problem -- : viniprovolo.com
-- HikaShop version -- : 5.1.0
-- Joomla version -- : 4.4.8
-- PHP version -- : 8.3
-- Browser(s) name and version -- : chrome

Good morning, I have an issue with the PayPal purchase. I used PayPal (not legacy) as recommended, configured all the APIs, and the system tells me that PayPal is set up correctly. Then I run a purchase test. When I click on the PAYPAL CHECKOUT button, a blank popup appears without providing any information. If I do nothing, it stays there forever, but if I close it, the screen to enter PayPal credentials appears underneath, allowing me to finalize the purchase. How can I resolve this?

oh yessss, it works perfectly, many thanks

francesco