WHMCS Integration: Too many redirects.

I have been testing the WHMCS Integration by trying to place some test orders. I have added a domain transfer to my cart and tried to add hosting as well. When I "Click to Continue" I get the message "WHMCS Integration: Too many redirects." and cannot go any further.

When I clicked onto the Wordpress dashboard and then clicked the browser back button, the cart came up correctly on the payment information screen.

I tried logging out of my Wordpress site and clearing history to see if I just had too much going on in the background, but I got the error message when I tried to place a domain transfer with no hosting in the cart.

Any ideas what I may have messed up? I'm using Resellerclub for the domain registrations.

Thanks!