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 may be unable to login. If so you need to go here and change your password, or if you forgot your old password go here.

Crowd passwords were set to expire after six months, and some of the Crowd passwords expired over the weekend. Unfortunately if you attempt login to Confluence or Jira and your password is expired you do not get a friendly reminder to change you password, your login is just rejected