While we can't share specifics, we suggest making changes to your content and reapplying for YPP. Also, you may want to take a look at our Help Center article on YPP policies which can provide you more insight: https://yt.be/help/AsbB . Hope this helps.
My channel was monetized for years. Then it was demonetized for “reused content” .. I then deleted all videos that was considered “reused content” but you guys still didn’t approve my channel for monetization (Which I think is a mistake)