We've received some reports that the hotel booking link is occasionally not working properly. The hotel is looking into that currently. You can still try, as you may get through. We've heard that trying different devices (mobile versus desktop) makes a difference. If it still gives you any trouble, hang tight and hopefully they'll get it resolved soon.
In the mean time, there's still a couple days left for panel submissions. If you have any really wonderful last minute ideas, now's the time to get them in!