There are several reasons why your AdSense application may have been disapproved, and the most common disapproval reason is because your application is a duplicate of an existing account. AdSense policies only allow one account per publisher, and it's against the AdSense Terms and Conditions to create a second account.

If you receive an email from AdSense saying your application has been disapproved for being a duplicate, you may associate your original account with your YouTube channel. The email from AdSense will provide details about your original account. 

Learn more about common AdSense application disapproval reasons.

* Nguồn: Youtube