Shoot, we posted an update about this on Twitter but forgot to post it here.
One of Conclave's hosting providers was hit by a massive DDoS
attack last night. For a few hours, the game was unavailable at playconclave.com but could still be reached at its backup URL of conclave.herokuapp.com. After that, our provider was able to mitigate the effects of the attack until it stopped.
We're waiting for them to post a post-mortem with more details and what steps they're taking to improve their defenses against future attacks. In the meantime, we're looking into whether having redundant providers for DNS (the service that was targeted) is an option.
If you're curious, this is a visualization of what the attack looked liked at its peak: