I can confirm that I'm having no luck logging onto Chaos, however I can DC travel and login to Light no problem. My stay on Light has been quite stable so far. However I'd like to return home to access my retainers/mail, so hopefully it'd be fixed.

It feels like Chaos might be having some technical issues? It's so odd that people are giving mixed reports like being able to log in certain characters, or newly created characters being fine.

I encourage people to go and also post here. It's a thread on the Technical Issues forums. It could be that Chaos is under some DDoS or there's some technical issues, since we got nothing from SE after the maint, all we could do is speculate...