WHMCS Wordpress Integration 1.4

Hi,

can you please check the below link, I cannot figur it out why it does not work.

I have my WP and WHMCS in the same directadmin server both are working fine.

https://www.hostingband.com/ozhan/https://secure.hostingband.com/clientarea.php/cart.php/?a=confproduct&i=0