Have you notice, that event in the latest stable version of prestashop (v 1.3.1), there still a bug that related to mail alert module.
I noticed this when i try to input my email address at our latest client online store for the product that is out of stock. The Notify me when available text link, when you try to click it, it won’t bring you anywhere, because there is a bug in the product.tpl file inside the mail alert module.
When Your Prestashop Won’t Send You Email
If you could not sending or receive email when a customer make a purchase on your store, then you could say “Houston we have a problem”. Email alert module in Prestashop 1.3.1 will works great in some hosting and not working at all in some.