Late last night I was doing some experiments with web builds on Cloudflare and I enabled "Force HTTPS" for attackmove.io. This broke mission loading and some authentication stuff. I then went to sleep without noticing the error and only fixed it when I woke up. Apologies! It's all resolved now, but there was an outage for about 8 hours.
I now get notifications no matter how late they occur so I will catch issues like this in future immediately.