I try to access the "div.prod_inner" on the following homepage (see image) for web scraping.
I use the HtmlAgilityPack and the code works on another homepage and also on "div.lay_main" returning one element.
This is the code I use (C#):
var productHTMLElements = document.QuerySelectorAll("div.prod_inner);
I also tried with
var productHTMLElements = document.DocumentNode.QuerySelectorAll("div.prod_inner");
and ".prod_inner" and "prod_inner" and it does not work either.
I expect the code to fill an array with all the products found on the page that are of class. But the array remains empty.
I am all new to web scraping. What do I do wrong, and how do I do it right?

You are not actually using HtmlAgilityPack you are using a library called Hazz that extends HAP.
I am not familiar with that, but using XPATH should work.