The best place to check is your Monetization page in Creator Studio: https://www.youtube.com/account_monetization …. From there, you’ll see an explanation with links to relevant resources. You’ll also see the option to reapply from that page in 30 days!
If your application is delayed, it’s usually for 1 of 2 reasons: you may not have enough public watch hours (Creator Studio shows public & private combined), or our team couldn’t come to a clear decision & we need multiple reviews. More info: https://yt.be/help/YPP-review