You needn't get panicked at this .If this is the case than they is some problem in filling of your form which needs to be rectified soon.You may also be able to upload your signature , correct photograph or any other documents correctly .

I suggest you to check your roll no and other numeric details correctly once again .You can also go to a cyber centre that fills student form so that in case the error is in uploading that can be identified .

Also some other reason may be

Age under 17 till December 2019.

Not having 50% marks in science in class 12th boards.

Not being able to pay for registration correctly

I hope this will help you

Good luck