Hey Rachel!

Generally, a candidate is not permitted or allowed to download the admit card if the dowloading time had exhausted or expired. If you want to know about a particular exam's admit card, you will have to mention the name of the exam name for which one is required to download the admit card. You may mention in the comment section or you may repost your question stating the required details.

Hello

You have not mentioned the examination of which admit card you cannot download before the   date is exhausted. If it is off JEE mains examination it is informed that when the releasing of JEE main admit card within 3 hours the service the server was the server became Jam condition. So you have to wait for this and even download the admit card even though it shows the expiry date of downloading admit card. After the date you expired most of the examinations doesn't allow to download their admit card

Hope this helps.