If you are trying to verify your email address as a new Adyen Customer Area user, you received an email verification link in your email. If you click on the link in the verification it will direct you to the Customer Area login page, where you can login for the first time. Make sure to use the link you received in your email and not the normal login page. If the verification link expired before you verified your email, please check How to resend the verification link.
After verifying your email address at first login you can use this link: Customer Area login page