The problem kicked off this morning with Redmond saying it was looking into errors within its caching infrastructure. In an advisory, the Windows goliath wrote “some users may be intermittently unable to view or access web apps in Microsoft 365.”
A range of Microsoft 365 online services are affected, such as Excel, the company wrote, adding “the search bar may not appear in any Office Online service.” Others impacted include Teams admin centers, SharePoint Online (users may not be able to view the settings gear, search bar, and waffle), and Planner.
According to DownDetector, complaints of the outage began to spike before 0900 ET (1300 UTC). There’s no sign of any resumption in services for the time being.
The software giant initially indicated the problem was linked to an “unusually high number of timeout exceptions within our caching and our Azure Active Directory (AAD) infrastructure.” It soon updated that its engineers had narrowed down a cause.
“We determined that a section of caching infrastructure is performing below acceptable performance thresholds, causing calls to gather user licensing information to bypass the cache and go directly to Azure Active Directory infrastructure, resulting in high resource utilization, resulting in throttling and impact,” Redmond wrote in an advisory.
Microsoft has battled its share of outages in recent months. A code change caused a four-hour outage of Azure Resource Manager in Europe in March and a month earlier Outlook was knocked out for a while.
In January, Microsoft had to roll back a network change in its WAN after it cause problems a range of cloud services, including Exchange Online, Teams, Outlook, and OneDrive for Business.
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