8:30AM Pacific — We continue to be in communication with Microsoft regarding these recent deferrals.  They have not yet been able to determine the cause of this issue, but they have escalated the issue to their senior engineers and have designated this as a high priority business-critical case.  We are pushing for updates hourly, and will post further information here once we have more information from them.

Per our previous post, we are encouraging customers to also contact the Microsoft support team to underscore the criticality of the issue, and we also suggest that customers whitelist our IP addresses within the Office365 system, as that may help to mitigate the frequency of deferrals.