This problem occurred recently - if I am not logged into Wordpress, I am not able to add products to my WooCommerce cart. It redirects to the cart page as it should but shows 'Cart Empty'. Works perfectly when I am logged in as a user in any role. I searched around and found this thread: http://wordpress.org/support/topic/plugin-woocommerce-cart-brokennot-adding-products
I've tried changing my session folder with a custom php.ini file but the problem is still persisting. I used Duplicator and set up an instance on my localhost - where it works without issues, so that tells me the problem isn't with the theme or the plugins. What other issues with hosting could be causing this?