It sounds like you're facing a frustrating issue with linking your AdSense account to YouTube for monetization. The rejection could be due to a variety of reasons, such as issues with your AdSense account's history, insufficient content or traffic, or possible conflicts with previous associations of the account. Even if you've followed all the steps correctly, AdSense has strict and sometimes undisclosed criteria for approval. Make sure your account details, tax forms, and content comply fully with their policies. Additionally, the quality and commitment of your content are important factors for approval.
To resolve the issue, contact AdSense support directly for clarification, and ensure your YouTube account is in good standing with no hidden violations. If the problem persists, you might consider trying a new AdSense account or seeking further help from the YouTube or AdSense forums. While the process can be frustrating, persistence is key, and communicating clearly with both platforms should help you move forward with monetization.