In order to get your builds working again, we need to reauthenticate with GitHub and other services used in your build.
When you log in to CircleCI via GitHub's OAuth, we get an API key to call the GitHub API, update the GitHub commit status, list your projects on the add projects page, etc.
We revoked all OAuth tokens to protect your GitHub repositories. The first time you log in to Circle, you'll have to reauthenticate the Circle GitHub application to get a new token.