Twitter's overload message

Heavy traffic may cause overload to any web site. When Michael Jackson died even Google went overloaded.

Click to enlarge

Now, there maybe a number of causes. It is not necessary o be any technical problem but if you want to find out what is making your twitter account inaccessible then there is a blog where twitter officially posts technical faults or any other bug.

Here's the link status.twitter.com. Here you will find any known issue as well as updates to all the problems after they are resolved.