Pro Sites signup/upgrade page is blank

My expectation of Pro Sites might be inaccurate so let me know what I need to do.

I have re-branded pro sites to "pro" so I was expecting new or existing users who visit to see the upgrade pricing table and be able to chose the plan they want. But the page has no content other than logo and menu. I have tried accessing this page as an unregistered viewer and as a registered user with the same result. While signed in I have seen and clicked the "Upgrade Options" button but it takes me to this same page with no content. I have tested this in many different browsers and still get the same result with no content.
What should I do?
Thanks for your help.