Hi Rubantin I added a product to the cart and it did show up. But check that the URL isn't swapping between the http and https connection, or different forms of the URL like nwn. or www. or anything like that when the cart items are lost.
Hi the urls are switching between .me and .pw the first screen on the cart is on .me hit checkout and it goes to .pw like Vince mentioned check in the admin under main settings that the url is correct.