Blog post
Blog Post
Lessons from Microsoft’s office 365 Outage: The Importance of third-party monitoring
By
When your software powers productivity for millions of users, trust becomes your ultimate currency. Trust is earned through transparency, clear communication, and unwavering reliability—especially when disruptions occur. Microsoft learned this lesson recently during a significant outage that took down two of its flagship services: Outlook and Teams.
What happened?
On Monday, November 25, Microsoft’s productivity tools Outlook, Teams, Exchange and SharePoint, key components of the Office 365 suite experienced a major outage. Microsoft shared it had resolved all of its issues with Outlook and Teams just after 3 p.m. EST on Tuesday, more than 24 hours after users first started reporting outages early Monday morning.
For millions in the affected European regions, it was pandemonium. Businesses, starting their day, woke up to disruption. Communication lines were severed, meetings were missed, and access to critical files was impossible. Some users faced patchy service—emails arriving without attachments, messages stuck in limbo—while others were cut off entirely.
The chaos exposed just how deeply reliant modern workplaces are on Microsoft’s productivity tools. According to Microsoft, Teams has 320 monthly active users. Outlook is just as indispensable to its 400 million users for email and scheduling. Losing access to these tools during business hours paralyzed workflows for countless organizations.
The impact was compounded by Microsoft’s communication which was mostly conducted via posts on X.
The lack of detail on Microsoft’s official status page left users frustrated, with no clear understanding of the issue, its root cause, or a timeline for resolution.
How was it detected?
As the outage unfolded, Catchpoint users were ahead of the curve thanks to our Internet Performance Monitoring (IPM) tool Internet Sonar, which flagged the problem in real time.
Visualizing the issue:
- Nov 25 3:35 AM ET: Internet Sonar detected anomalies across multiple European regions, showing HTTP 404 and 503 error codes.
The incident was also verified by Internet Stack Map, which showed dependencies like the CDN and DNS services were all running normally; the outage was localized to Microsoft office.
For our customers, this early detection provided invaluable insights before Microsoft acknowledged the issue publicly.
Key lessons
Microsoft’s outage offers critical insights into the complexities of cloud infrastructure. Here are the key lessons to take to take away from this incident:
#1 In a connected world, failure is inevitable
In our Internet Resilience Report 2024, we interviewed over 300 global digital leaders about digital and Internet Resilience. One of the questions we put to the field was about their reliance on third-party providers. All respondents, bar 1%, said they had some reliance on third-party platform technology providers and 77% said this was extremely or highly critical to their digital or Internet Resilience success.
We can’t remove these dependencies—they are numerous and deeply intertwined, enabling our sites and applications to function and keeping our systems secure. Yet, as Werner Vogels, CTO of AWS, famously stated, “Everything fails all the time.” This inherent fragility means that we must be prepared for inevitable failures.
A crucial aspect of this preparedness is monitoring SaaS applications, which lie beyond the control of your IT team, as well as APIs. APIs are the connective tissue of our digital world, powering transactions, communications, and countless services. Their hidden behind the scenes nature should not prevent them from getting the proper monitoring and observability attention that they deserve. API failure can have several catastrophic impacts on users, including functional disruption, data inaccuracies, loss of features, delayed updates, and security concerns. Effective API monitoring helps ensure swift detection and response to disruptions, minimizing their impact and maintaining service reliability for end users.
#2 Status pages are often unreliable indicators of service health
During the service disruption, Microsoft's status page initially lacked timely and accurate updates. Instead, the social media platform X became the primary source of information. Each cloud provider has its own criteria for deciding when to update their status page, and it’s rarely a case of deliberately keeping users in the dark. Many organizations do use social media to communicate outages, but it comes with its own set of risks. Social media can be unreliable and often falls short in providing the kind of detailed information IT teams need during a crisis. As a result, Microsoft users were left frustrated, lacking clarity on the issue, its root cause, and when it might be resolved.
A better way forward: Leveraging Internet Sonar and Internet Stack Map
During the outage, our users leveraged two tools in our portal that enabled them to get ahead of the service disruption: Internet Sonar and Internet Stack Map.
- Internet Sonar is a powerful tool that eliminates guesswork by providing real-time, independent Internet health data. Using Internet Sonar, you’ll know whenever a third party has an outage, where they have it, how long it's been going on, and whether or not it's likely to affect you. Further, Internet Sonar doesn’t just tell you when a site is down after people tweet about it. This means no finger-pointing, no war rooms, just straightforward, intelligent, and reliable Internet health information so you can get ahead of productivity or experience-impacting 3rd-party incidents.
- Internet Stack Map shows a live view of the health of your digital service and the services it depends on. By automatically discovering third-party dependencies, it helps organizations understand the health of their digital ecosystem at a glance. When one component fails—such as Microsoft Office in this case—it’s clearly highlighted, making root-cause analysis seamless.
Consider what this could mean for an e-commerce site as in the example below.
If a third-party is experiencing an issue, Internet Stack Map provides an essential single point of reference. If all components are green, it suggests that the outage is not impacting the application’s availability or performance. This minimizes panic, avoids unnecessary escalation and helps teams to focus on what truly needs attention.
The importance of independent monitoring when the chips are down
The Internet is a complex web of interdependencies. Like it or not, we’re all reliant on each other and disruptions are inevitable. This incident shows why third-party monitoring is crucial. Clear, independent, and reliable information during outages can make all the difference when disruptions occur. When your workforce can’t connect, relying on posts from X or status pages isn’t enough. To maintain trust with your users, you need tools that provide real-time, independent insights into Internet health. With the IPM tools in the Catchpoint portal, you won’t have to wait for your third-party provider to tell you there’s a problem. You’ll already have the answers.
View our live Internet outages map powered by Internet Sonar
Learn from recent Internet outages
This is some text inside of a div block.
