1. Wrong or inactive email IDs.
2. When you create account in this site, it sends an email for verification. You need to click a link in this email to be able to access your account. If your email provider puts this email in Spambox then you may wonder that you never received that email. You should check your INBOX and Spambox both after creating account.
   

You may email support@123iitjee.com if you need further help on this.

Enrolment Key: Enrolment key will not be asked by the site after your login account is activated. Login is activated after admission procedure mentioned here is followed.