Looks like the authentication servers will be undergoing some maintenance this evening, March 16th from 11pm PST/2am EST to 1am PST/4am EST. Here's the full announcement:
We'll be performing maintenance on our authentication services this evening which may impact the ability to log in for some players. The maintenance will begin at 11:00 PM PDT, March 16 and last until approximately 1:00 AM PDT, March 17.
So if you were planning on logging in tonight, you may want to do it before the maintenance starts. If there are any extensions to this maintenance, we'll be sure to let you know!