Yeah, we are experiencing problems with some server certificate that expired. That’s why you couldn’t register and get your activation key. I’m very sorry for the inconvenience. We are working on getting everything up to speed again as we speak.
If you email me your name and email we can register for you manually here. Then you will receive your activation key on your email, as if you did it yourself. My email is niels at animationpaper.com.
EDIT: Never mind! Since you registered to write on this forum, I could find you in our database. So I will be registering manually on your behalf so you can get your activation key in a few minutes. I hope you enjoy Animation Paper! Thanks!