No printing list

I’m building an e-commerce site with woocommerce and theme Flatsome, I’ve add the plugin Pdf invoice and shipping list. When I process an order in the right section of the page I can create and delete the invoice and the printing list but when I click the buttons for view them, they only refresh the page and they don’t open or show me the invoice or the shipping list. At the same time the invoice is send to the customer’s e-mail so it seems to work. In the setting panel I can only customize the invoice template but nothing about the shipping, is that right? How can I solve it?