The application that provides account-related functions (self-signup, inviting other users, and password management for cloud.gov [non-SSO] accounts) was unavailable due to the failure of a Redis instance that the application depends upon.
Once we identified the issue, we repaired the failing instance, and the application returned to normal operation.
The dashboard relies on Redis as well, so it was also affected by a failing Redis instance for a short time. We received an alert for this and fixed it.
We are reviewing and updating the configuration of our alerting systems. This will ensure that when similar failures occur in the future, we will be able to respond quickly and restore service before any users are impacted.