Drafting is being unstable right now, so we've temporarily disabled it while we sort things out. If you've completed the drafting portion, you'll be able to resume your event once we're able to turn drafts back on. Sorry for the delay, but you won't lose your progress.
Still seems to be down, their status page had previously said it was available again but it looks like they took it back offline due to instability: https://magicthegatheringarena.statuspage.io/