You can’t use that AdSense; as it wasn’t created from your monetization page and your website was disapproved.Click the ‘create or link an AdSense account’; select create an account, and use a different email address to create a valid AdSense account to connect to your channel.You’re trying to connect AdSense from the AdSense signup page. You need to start from the page linked below.https://studio.youtube.com/channel/UC/monetizationIf you don’t see the option, your channel hasn’t reached both application thresholds.