Eshop add to cart button not working

Hi, I have this eshop plugin installed in this site.
I add default sample data to test if its working, and Add to cart button is not working and it always say prompt "Shopping cart is empty".

Hello Carl,

Thank you for using our EShop Shopping Cart extension. The reason maybe because cache setting on your site. Please submit a new ticket to EShop category to send me the your site information so I can help you to check and correct it for you.

Hope to receive your ticket soon.

Sincerely, Giang

I have the same problem! When i push "ADD TO CART" it prompt "The cart is empty"!
.
I was making some test. I noticed that the problem exist on Microsoft EDGE Browser!

Dear Giorgio,

Please submit a new ticket to EShop category to send me the super admin account to your site so I can help you to check.

Hope to hear back from you soon.

Sincerely, Giang