So I think it's possible that they were shut down by an international coordinated criminal justice raid, maybe even because of CP.
Well, it's a possibility, proxy.is (that is in fact their proxy provider, not their host) is also down, and among the two lines still readable through a google search, they were "an anonymous alternative to CloudFlare". While a whois tell that they were based on Seychelles. Therefore, the perfect service to use if you intend to share not really legal content online.
Perhaps that Anonfiles haven't been targeted directly, and only suffer from proxy.is fall.
The only thing I can say about them directly is that they lost their DNS records between
Monday 3:14AM GMT and
Tuesday 2:56PM GMT. Therefore, for nearly a full week they still had their DNS records, what don't match with a take down done by the authorities. It looks more like a voluntary decision ; they kept the DNS records the time to understand that proxy.is will never comeback alive again.