Can't See product listing

Hello. I added 2 products to specific category that I have created.
Then I go to MEnu- create new menu item and select product listing.
Nothing happens, the products listing don't show up and I end up with a blank page like this:

scalex.pl/index.php/towary

I don't know whether it's a bug or I'm doing something wrong.

How to fix it?

Warmest Regards

you don't have any products in your main product category and the default configuration of products listing only displays products directly attached to that category. That's why you didn't see any products.
I've changed that for you in the HikaShop options of your menu with the access you provided by email and it's displaying all the products now.