Try a different browser to log into Google AdSense. For example, if you usually use Chrome, try Firefox or Internet Explorer. If the error to connect to AdSense appears the same in both browsers, usually the website is down.
(AdSense login was working for me at the time of writing this post)
Up until Thanksgiving Day I was averaging $9.28 a day. Since then it has gone in the tank. While I know the traffic is about the same. It has dropped away to almost nothing. Something is not right here folks.