The current situation as far as I can tell right now:
The affected website IPs are up, and most sites on them seem to be working. Some sites are still down, showing 404 errors on the website and “421 Home directory not available”. Usually this would indicate a problem with the hosting volume, but other sites on the same hosting volume are working, so it’s not entirely clear what’s the deciding factor there.
Meanwhile, I have not received any clear information from iFastNet yet regarding what is happening here exactly. I’ll keep you updated as soon as I know more.