At 7:35 p.m. PST on February 6, 2023, Zscaler Digital Experience (ZDX) saw a substantial, unexpected drop in the ZDX Score for Microsoft Outlook services in North America. Upon further analysis, we noticed high page fetch times highlighting a Microsoft Outlook outage.

ZDX Dashboard indicates most impacted applications

The ZDX heatmap details the impacted locations:

ZDX: Outlook outage across North America

With ZDX, customers can proactively identify service issues and quickly isolate them, giving IT teams confidence in the root cause while reducing mean time to resolve (MTTR) and first response time (MTTD).

ZDX Score highlights Microsoft outage

A ZDX Score represents all users in an organization, across all applications, locations, and cities. You can see the score on the ZDX Admin Portal dashboard. Depending on the time period and filters selected in the dashboard, the ZDX Score will adjust accordingly on a scale of 1 to 100, with the low end indicating a poor user experience.

As we drill into the North America users, we can see the ZDX Score drop into the poor experience range. That correlates to higher page fetch times.

To get additional details, you can simply mouse over the ZDX Score to understand the page fetch times. In this instance, the times are between 52,743 and 106,838 ms, and eventually web probe timeouts, which renders the application unusable and impacts overall end user performance.

ZDX Dashboard shows low ZDX Score with high page fetch times

ZDX Dashboard shows web probe timeout

With further analysis, you can see the ZDX Score for Microsoft Outlook dropped to poor around 7 p.m. PST, on February 6 and began to slowly recover, but continued to face issues until 8 a.m PST, February 7. From within ZDX, service desk teams can easily see that the service degradation is limited to a single region and quickly begin analyzing the root cause.

ZDX dashboard indicates the Microsoft Outlook outage and slow recovery

ZDX can quickly identify the root cause of user experience issues with its AI-powered root cause analysis capability. This spares IT teams the labor of sifting through fragmented data and troubleshooting, thereby accelerating resolution and keeping employees productive.

With a simple click in the ZDX Dashboard, you can analyze a low score, and ZDX will provide insight into potential issues. As you can see in the Microsoft Outlook outage, ZDX highlights the low region score and poor performance for Microsoft Outlook.

ZDX AI-powered root cause analysis indicates the reason for the outage

When there’s an application outage, many IT teams turn to the network as the root cause. However, as you can see above, ZDX AI-powered root cause analysis already verified that the network transport wasn’t the issue; it was actually at the application level. You can verify this by looking at the CloudPath metrics from the user to the destination.

ZDX CloudPath indicates no networking issues

According to the Microsoft Outlook status page, the outage was reported at 7:30 p.m. PST, which correlates to the ZDX data above. The outage was confirmed in a tweet suggesting a “recent change” contributing to the impact.

Source: Twitter

As Microsoft Outlook services started to recover, there were still residual impacts detailed on the Microsoft Service Health page until 8:05 a.m. PST.

Source: Microsoft

With ZDX Alerting, our customers were proactively notified about end user problems, and incidents were opened automatically with our ServiceDesk integration long before users started to report it. From a single dashboard, customers were able to quickly identify this as a Microsoft issue, not an internal network outage, saving precious IT time.

Zscaler Digital Experience successfully detected a Microsoft Outlook outage along with its root cause, giving our customers confidence in who was impacted, their networks, and devices, averting critical impact to their business.

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ZDX helps IT teams monitor digital experiences from the end user perspective to optimize performance and rapidly fix offending application, network, and device issues. To see how ZDX can help your organization, please contact us.