I can't see related products

-- url of the page with the problem -- : www.saradavies.gr/index.php/brands/kyboe/product/1-sw-001
-- HikaShop version -- : HikaShop Essential: 2.6.2
-- Joomla version -- : Joomla! 3.5.1

Hello Hikashop team!
I have 4 products in category but in the product page the related product they are not visible!

What we do in this case?

I found the solution in other topic.
www.hikashop.com/support/documentation/i...ct-form.html#related
thank you