Some Twitter users are facing the problem using the service. Twitter has acknowledged that some Twitter users may experience the problem using the social networking site.
Some users may be experiencing an issue with our service. Our engineers are currently working on this issue.
The status on the twitter shows that twitter is working on the problem since last 2 hours.I will keep on updating you about the status of the service.Even you can check the status of the service by going to status page.
Update:The twitter has posted that issue has been fixed the engineers.They posted about the update saying,
As of 8:50am PT, this issue has been resolved.