From Blackboard Managed Hosting:
As you may already know, this weekend Blackboard Managed Hosting had an operational issue which may have impacted service availability of your Blackboard environment. The issue started on Sunday, 11/29 at 05:30 AM US Eastern and was resolved this morning (11/30) at 05:40 AM US Eastern causing intermittent outages. During this time our notification system was also impacted, emails were queued up and some notifications did not go out, so you may not have been alerted when your system service was restored. Blackboard would like to apologize for these issues and any inconvenience this may have caused. Please note that a formal report explaining these events in greater detail will be made available later this week.