Hey Amelia,

While uploading your document, there may have occurred some error and it may not have uploaded properly and completely, that's why you are not able to preview it. You can try once again by going in some cafe or if you want to take no risk then, you can do one thing. You can pay an amount of RS. 100 and make changes in your form. Then update the form once you are sure of everything this time.

You can also have a talk with the admission staff of DU. You can find the official numbers on the official website of DU.

Hope that helps and your problem gets a solution! :)