I had this problem with consumerreports.org, pandora.com, and buy.com (I could access the site but they would always cancel my orders) and other Internet retailers due to a non-US IP address. Whenever it happens, I log into
http://www.publicvpn.com/, which shows a US based IP address. Also, it is a safer way to surf the net when accessing hotel wireless networks and public wifi hotspots.