Hello Student

Possibly There will be some kind of mechanical defects in the portal might be. Wait for sometime at least  6-7 days and   try again for  restart yourself. Your Delhi University PG portal may be very much busy and the Server condition is not so well possibly. After 6 -7 days you may ask to the respective authority and may  apply for  reconsidering of your case for another time within a short period of time  to allow you for registration of your candidature.

Hope this will help.