I think it's the illuminated server (I have an illuminated account) - I can't raise a ticket for this because I can't get access. It may be a regional thing - I'm in the UK and the error appears to be with Cloudflare in between me and the x10hosting servers (although I have a site that uses Cloudflare and that's fine). Earlier today I was getting a different 500 error, not related to Cloudflare, though. My websites on the server are fine, as is FTP.