You should've received an email with additional details. 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 to relevant resources. You’ll also see the option to reapply from that page in 30 days!
We'd like to understand this better. Could you please help us with a screenshot of what you see on this page: https://goo.gl/BB2MFg ? Keep us posted.