cant reach checkout

-- HikaShop version -- : 2.3.1
-- Joomla version -- : 3.3.3
-- PHP version -- : 5.3.28
-- Browser(s) name and version -- : all 5 major browser latest versions

When the popup displays after adding a product to the cart most of the time if you click proceed to checkout it will not load the checkout page and the server will time out. Occasionally this will also happen when clicking the cart link at the top of the screen. I have gone through the forum and all I could find that may be causing the problem is sef urls which are all turned off. Occasionally it will take you to the checkout but majority of the time it will not.

This is on a website that is up and running so the sooner the better, thank you in advance.

Thank you,

Chris Murdock