Happened to me this AM too. It seemed like they were having issues with authentication. The 1st time I reset it, it didn't take and I was prompted to do it again. 2nd time, the System Preferences app on my Mac hung and I had to force quit. 3rd time, I was able to successfully reset my password.
Then upon logging in on all my devices, handoff for phone and messages didn't work. I had to reenable it in messages, FaceTime, and Phone settings on both of my phones. Overall, about ah hour wasted setting everything back up again.