Weird problem with Walmart.com

hello

i have a very strange problem when I am connected to Internet via R8500 router. I cannot navigate Walmart.com website. I can open it but it doesn't matter where I click nothing happens. I tested all my devices connected to the same network (iPhone, iPad, Windows laptop, Windows desktop) same problem. But as soon as I turn off wifi and use cellular data the website works or if I connect to a different network it works. I know it's a very strange problem, and only with Walmart website but I tried anything ( reset the router., reboot the modem and the router ) still doesn't work

also I tested via vpn and it works 

any advice? 

Thank you