Our engineering and operations teams have identified the issue with the Atlassian Account authentication and are working on a fix. Next update in 30 minutes.
Posted 5 days ago. Jun 12, 2018 - 21:56 UTC
HipChat is currently experiencing and issue with forcing existing users to login with Atlassian Account. We are very sorry for the inconvenience. We are investigating and will have an update for you soon.