Our server has been under a constant DDoS attack for the last 7 hours. Once this stops then authentication should continue normally. We do have OFFLINE KEYS available for UNL members.
Just yesterday I read about the EVE online servers having recently been taken offline due to a Ddos attack as well.
Sounds to me like someone is trying to cause trouble around the net.
I am still able to authenticate my trainers online, but have to wait a minute or so for it to activate.