It is official, finally there is a tweet from Google about it. The real time reporting feature is not working for lots of websites all over the world for the last 2 days.
However, Google says there is a fix for that. Try clearing your browser cookies or access the analytics report using incognito browser window. Here is how you can do it on Google Chrome.
Here is the error which I get when trying to access the report.
Google says the problem will be fixed within 24 hours.