after updating to 2.3.5 the checkout page not work

-- HikaShop version -- : 2.3.5
-- Joomla version -- : 3.3.6
-- PHP version -- : 5.5.19
-- Browser(s) name and version -- : chrome
-- Error-message(debug-mod must be tuned on) -- : Fatal error: Cannot pass parameter 1 by reference in /web/htdocs/www.terapiaperacufeni.it/home/plugins/system/custom_quantity_tax/custom_quantity_tax.php on line 110

hi
after updating to version 2.3.5 the checkout page is no longer visible. The cart module if enabled on all pages of the site, the site itself is no longer visible.

What can I do to solve the problem. Thank You

Hello,
You'll just have to un-publish the "HikaShop tax calculations override plugin" through your plugin manager.