Please read the FAQ I linked to for clarification on what types of music streams are allowed.
Q. Can I use my channel to play music like a radio station?
A. No. The broadcasting of radio-style music-listening shows is an experimental program and is currently reserved on a very limited basis for approved music labels. If you have the necessary rights and meet the same criteria listed at music.twitch.tv for contributing music to the Twitch Music Library, you can apply for special authorization from Twitch.