User blog comment:DaNASCAT/Technical Update: June 11, 2013/@comment-4625170-20130613114305/@comment-957747-20130614172241

Twitter's API was changed back in March of this year. Twitter was urging users that were using their 1.0 version of their API to switch to Twitter Timelines. It seems, now, that Twitter has finally retired it's old API and is only supporting the new Timeline API.

You can read the discussed change on Twitter's site.

The Help page, has also been updated with step-by-step instructions on how to set up the new Timeline.