If you are using a Crowd id to login to Confluence, rather than a SLAC windows or unix account id, your password may have expired and you will be unable to login. If so you need to go here and change your Crowd ID password, or if you forgot your old password go here.

Crowd passwords are set to expire every six months, and the Crowd passwords started to expire in recent days. Unfortunately if you attempt to login to Confluence or Jira and your password has expired you do not get a friendly reminder to change you password, your login is just rejected.