UPDATE 8:05pm PT - The issue has been resolved and all users are able to sign into their sites.
UPDATE 8:02pm PT - Tableau Engineers have isolated the issue and working on mitigation steps.
Next update will be posted by 9:00pm PT, or upon resolution.
Tableau Online is experiencing intermittent sign in failures right now where users cannot log into their sites. Tableau Engineers are engaged and investigating the issue. We apologize for the inconvenience.
Next update will be posted by 8:00pm PT.