The site was assigned a new IP from the ISP and no one told me about it.
If you are talking about the PayPal site, it changes ips all the time. That problem isn’t new. I found it in September of 2010.
http://forum.mikrotik.com/t/walled-garden-and-ssl-sites-intermittent-problem/40829/1
Here is the script I had to use to get PayPal to work with the walled garden.
http://wiki.mikrotik.com/wiki/PayPal_with_hotspot_and_walled_garden_bypass