Same problem. Apparently servers that usually have thousands of players now only have hundreds, meaning that much more around the world is having the same issue. Also, for some reason, when I tried to update my skin it doesn't work.
Yep, happening on my server as well. Seems to have something to do with the new ID system that will soon allow us to change our names. The servers are unable to authenticate so they won't let anybody in. If you're running a server you can temporarily switch online-mode to false as a "fix"
(friend i was playing with has same problem too)
Edit: Disregard, confirmed working again.