During your first registration, you need to confirm your email address. You can confirm your email address by clicking on the URL in the confirmation email. You can request a new confirmation email trough this link.
Make sure to check your spam folder.
Did you reactivate your membership?
When reactivating your membership there's no need to confirm your email address again. Your email address has been confirmed during your first sign up. Please ignore the message you get while reactivating.