Thanks for reaching out – you should have received an email and a message with more info in Creator Studio which includes detailed resources and what to do next. Note: if you were removed from YPP for policy reasons, you can always reapply in 30 days.
You can apply 30 days after you received your rejection email. You’ll want to make some changes to your channel before you apply again. Check your features page to see if you can now re-enable monetization. More info: https://yt.be/help/d8W5