June 8-12, 2025
Join ThousandEyes at Cisco Live 2025

Outage Analyses

Azure AD Outage Analysis: December 15, 2021

By Mike Hicks
| December 16, 2021 | 1 min read

Summary

On December 15, 2021, ThousandEyes detected a widespread Azure Active Directory (AD) outage. The following is an analysis of the outage, which will be updated periodically as we have more information to share.


[Dec 15, 9:30 pm PT]

ThousandEyes detected a widespread Azure Active Directory (AD) outage lasting ~1.5 hours from ~00:50 UTC – 2:25 UTC, which may have impacted users around the globe from signing in to Microsoft services like O365. During the outage, authentication requests were returning HTTP 503 service unavailable errors. Azure reports that it mitigated the issue at around 2:25 UTC by rolling over to redundant infrastructure, which cleared the issue and restored service availability. 

Live link to view the Azure outage in ThousandEyes here. No login required.

Figure-2-Azure-AD-Outage-Dec-15.png

Figure-1-Azure-AD-Outage-Dec-15.png

related blogs

Blog Thumbnail: Zoom Outage Analysis: April 16, 2025
Outage Analyses
Zoom Outage Analysis: April 16, 2025
On April 16, Zoom experienced an outage that impacted users globally. See how the outage unfolded in this analysis—more updates will be added as we have them.
By Internet Research Team | April 16, 2025 | 9 min read
Blog Thumbnail: The Top Internet Outages of 2024: Analyses and Takeaways
Outage Analyses
The Top Internet Outages of 2024: Analyses and Takeaways
Explore some of 2024’s most notable Internet outages and application issues, along with key takeaways to help your ITOps team improve digital resilience in 2025.
By Internet Research Team | January 21, 2025 | 12 min read
Blog Thumbnail: Netflix Broadcast Disruption: Lessons for Major Live Events
Outage Analyses
Netflix Broadcast Disruption: Lessons for Major Live Events
The issues Netflix experienced during the Jake Paul vs. Mike Tyson boxing event leave valuable lessons for ITOps teams seeking to assure flawless digital experiences.
By Mike Hicks | December 20, 2024 | 14 min read