Hello Harshadeep Paul

I hope you are doing good. I would like to tell you that multiple registrations are strictly prohibited in jee mains exam to maintain authencity of students on a big scale. If you have registered already ,  required credentials are always sended on registered email and phone number . I would suggest you to check them and entered it correctly after clearing cache memory of your machine . If issue is still not resolved, send an email to NTA for your problem ,they wil always revert back to help you though take some time but they will help

If you have any other doubt then you can always reach us to clear them :)

we are always available to help you out and guide you

Thankyou