Were you able to sit for counselling.?  Did your result was declared? Please tell me how you handled the situation? Because I alo couldn't upload my marksheet for JEE Advanced 2019.

Lingam that could create a problem for you because the 12th marksheet is asked to be uploaded on or before 5th June 2018 before the counselling date in order to confirm for the students who have given 12th board exam this year have got more than 75% in 12th board exam or not because you know that without 75% you are not eligible for JEE Mains exam and if you can't JEE Mains exam then you will never be eligible for JEE Advanced exam because it is necessary to clear JEE Mains exam.

So, I don't know whether you will be able to sit in the counselling or not but you still have time because the result will be declared on 10th June 2018 and the counselling will start in the third week of June so you can do one thing if you don't have original marksheet so you can download it from the official site from where you have seen the result online in the form of PDF file or take a screenshot convert it into PDF.

Then send a mail on the official mail id of JEE Advanced apologising how you missed to upload the marksheet and attach this PDF file with mail. Also, mention your name and JEE Advanced registration number in the mail. Mostly they will accept it and you can get free from the tension. To clarify your doubts you can also call on the official number in the working time.

Feel free to ask if you have any more queries. All the best!!