Microsoft 365 suffered 5 hour login breakdown yesterday

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Published onSeptember 29, 2020

published onSeptember 29, 2020

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Yesterday afternoon Pacific time (officially from 2:25pm PDT to 7:25PDT), Microsoft 365 userswere unable to log into multiple Microsoft 365 services that use Azure Active Directory, including Outlook, Microsoft Teams, Office.com, Power Platform, and Dynamics 365. Users who were currently logged in to services were not affected, and the services themselves continued to run, but anyone logged out was unable to log in during most or all of the 5 hour window.

Microsoft updated its Microsoft 365 admin center Service Health page last night to report a final status, that “(a)fter extended monitoring of our service, we have confirmed that the issue has been fully mitigated and is running within optimal service levels.”

Microsoft is still investigating a root cause, with a post-incident report promised within 5 business days, but did post a preliminary cause, after initially ruling out a code change that was rolled back early in the outage, without success:

Preliminary root cause: A code issue caused a portion of our infrastructure to experience delays processing authentication requests, which prevented users from being able to access multiple M365 services.

We’ll keep you posted on any further reports.

Kip Kniskern

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Kip Kniskern

With KB5043178 to Release Preview Channel, Microsoft advises Windows 11 users to plug in when the battery is low#

Copilot in Outlook will generate personalized themes for you to customize the app#

Microsoft will raise the price of its 365 Suite to include AI capabilities#

Death Stranding Director’s Cut is now Xbox X|S at a huge discount#

Outlook will let users create custom account icons so they can tell their accounts apart easier#

Microsoft 365 suffered 5 hour login breakdown yesterday#