Can you please share the complete process you are following or screenshots here. Are you facing difficulty at very first step "authentication" or later stages?
For updating / confirming details of class 12 you first need to authenticate yourself by providing
JEE Main Application Number, JEE (Main) Roll Number and your Date of Birth in format DD/MM/YYYY.
In some cases, based on data sent by the Boards, the class 12th/Qualifying examination information has been updated.
If you details are already available simply check and confirm. If your details are not available update details by selecting Board, Year of passing and Roll No.
The last date of confirming/updating such records is 10th June, 2015
Copy of Official Notice