Best way to keep up to date is to join the discord server. You don't have to participate in the chat, but you can check the announcements there to know what's going on.
If connection failed only today but not the past few days, Kami is right and it's because of the DDoS attack that is currently happening and being worked on. The devs are upgrading protection for these matters, so it should be fine in the future.
However, if you tried connecting and had no success prior to this day (12/15), it's possible that you weren't aware of the new re-release client that was uploaded on 12/10 (past Thursday). Download the new client (version 0.01R) if you didn't already the past 5 days.