Microsoft Outlook.com went down last night, but normal service seems to have resumed

Were you affected by the outage?

Microsoft Outlook.com went down last night, with the website throwing up error messages from around 5pm UK GMT/ 10am Pacific Time.

The outage lasted around three hours, on and off, with Microsoft's Office 365 Service health site slow to update initially, announcing "Everything is up and running" when there was a clear problem.

Meanwhile, Twitter started to fill up with hundreds of messages complaining about the outage.

— Ricardo Wagner © (@ricardowec) October 6, 2016

Eventually, Microsoft admitted "Users may be unable to connect to the Outlook.com service", adding that it was "analyzing the affected infrastructure to determine the cause of impact".

This turned out to be that a "portion of the capacity responsible for routing connection requests to the mailbox databases became degraded", which meant Microsoft had decided to shift "traffic to a healthy portion of the infrastructure to remediate impact".

By 8pm UK time last night, Microsoft announced that Outlook.com was back up and running.

The outage didn't affect everybody - it was probably dependent on which of those "degraded" connections your box was attached to - and was mainly confined to the US, but at least one member of Computing staff had acces troubles last night.

Microsoft service outages are never a light matter, however, with growing reliance on cloud ecosystems (Microsoft itself pushes the cloud-based Office 365 email server as a preferred end user port of call) meaning a greater risk to enterprise productivity.

As Mimecast commented to us last time there was a major Azure outage, things can really only get worse in this regard.