Sorry this doesn't look like a WHMCS site...

So I'm getting a strange error message now on my signup page -

Sorry this doesn't look like a WHMCS site at [http://www.downlinemagnet.com/clients/] Make sure your WHMCS Integration settings are pointing to the correct URL and that the WHMCS site is set for the Portal template in Setup | General.

Here's the link to the page.

Any clues what's happening here? Portal theme is activated, and when you got to that link, it all looks good to me. Any ideas?