Helle @YouTube my channel demonetize and they say me found duplicate content and reapply after two times they still not approve and my creater support is disabled. So i can't find exactly which video is duplicate they not show me and i have 816 videos on my channel. @TeamYouTube
You may wanna take a look at our Help Center article on YPP policies which can provide you more insight on this: https://goo.gl/Rtn6gs . You can refer to the article, make changes to your content if required and reapply after 30 days. Hope this helps clarify.