Please make sure you are trying from a supported web browser like Internet Explorer, Chrome, or FireFox. I checked via Safari as a test and it seems that it does not work correctly when you try to sign up for the beta on that web browser.
As of right now, I can see the application and it still works so I'm assuming there are still spots. You can access it by going here or here.
Please try that out and it should work.
Did this solve your problem?
Sorry this didn't help.
Great! Thanks for marking this as the answer.
How satisfied are you with this reply?
Thanks for your feedback, it helps us improve the site.