Microsoft experienced a multi-day outage last week impacting its Outlook.com, Calendar and certain SkyDrive services.
In a status update, Microsoft attributed the outage to a failure in a caching service that interfaces with devices using Exchange ActiveSync, including most smart phones. The company said this failure caused these devices to receive an error and continuously try to connect to service, resulting in a flood of traffic that was not handled properly. Restoration required that some customer be temporarily blocked by Exchange ActiveSync until traffic volumes allowed it.
