Shopping Cart Module Times Out?

This is an problem that I can't seem to figure out. I have the shopping cart module set up to show the customer what they added, but when they click proceed to checkout on the module the connection times out. I also have a shopping cart / checkout link on the top nav and that works just fine. Has anyone encountered this issue? The site is currently thermal.core101dev.com.

Thanks

The problem is that you activated the option "Force SSL on checkout" of the configuration but you didn't setup a SSL certificate on your website.
For example that URL does not work either because your server doesn't have HTTPS working:
thermal.core101dev.com/index.php

If you turn off that option, it will work again.