This information came from Blackboard today:
On Tuesday, November 2nd, papers submitted to SafeAssign were not being processed. The outage was caused by a storage failure related to continued high submission volume. It took some time to identify the cause, but thereafter service was quickly resolved. As part of the resolution, we have added storage capacity to be more reliable and robust. We believe the system is stabilized and papers are now being processed. There remains a backlog of papers that are queued for processing; this will occur over the next few days and we expect the system to be completely caught up by November 9th.
We apologize for this inconvenience. Our teams are working diligently to monitor the situation and correct any further problems.