Hi there, thanks for reaching out. To confirm, We're you a part of YPP earlier and got demonetized or that you've applied and were rejected now? Also, help us with the screenshot of what you see on this page: https://goo.gl/297Xrv . Keep us posted.
You should have received an email and a notification with more info in Creator Studio. Take a look at those resources and note that you can always reapply for the YouTube Partner Program again in 30 days.