Thanks for reaching out. Were you a part of YouTube Partner Program earlier and now demonetized, or is it the first time you've applied and were rejected? Let us know.
If you upload content from multiple sources, or reupload/repurpose someone else’s existing content then you won’t be eligible for YPP. Check out the FAQs and best practices here: https://yt.be/help/reused-content …. Let us know if this clarifies the issue.