What should I do? The server seems to be down with one day left for JEE Mains registration.

If the server is down and you are unable to complete your JEE Mains registration, you should try the following steps:

1. Wait for a few hours or days
2. Try filling the form at late hours or early morning
3. Use a different browser or device
4. Contact the JEE Mains helpdesk
5. Keep checking the official website for up

Due to excess traffic on the website, server down usually happens. You can try refreshing the site. Wait for some time and then revisit the website. Check your internet connection. If none of these works, you can reach out to NTA addressing the issue you are facing and the deadline.