Error by Add to cart

-- url of the page with the problem -- : wolfgang-fuchs.at
-- HikaShop version -- : 4.2.3
-- Joomla version -- : 3.9.16
-- PHP version -- : 7.3
-- Browser(s) name and version -- : Firefox
-- Error-message(debug-mod must be tuned on) -- : Cannot pass parameter 3 by reference

Hello, for some time now I have received an error page when clicking on "Add to cart"

Joomla 3.9.16
Hika Shop Starter 4.2.3
PhP 7.3

What can i do?

Hi,

That's an issue with the legacy checkout.
Please turn off the "checkout legacy" setting of the HikaShop configuration to use the new checkout and you won't have the error.