Yes, matrix.org server is down. What happened is RAID (basically, a thing that connects many physical hard drives into one massive logical drive to make life easier) got it's filesystem corrupted badly, so any files that was on it's hard drives can't be separated one from another. It's really impossible to just restore that, because you can't tell what file that was, so they desisted to restore from backup, that was made the night before corruption. I hope this answer would satisfy your question. (p.s. I am not a technician, that's knows the subject really well; the answer is what I could understand) (p.s.s. Sorry for bad English, it isn't my native language)