Microsoft is investigating an issue that is keeping some users from being able to access Microsoft 365 Online and the admin center for Teams on Thursday.
The problem kicked off this morning with Redmond saying it was looking into errors within the caching infrastructure. In an advisory, the Windows goliath wrote that "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 online, the company wrote, adding that "the search bar may not appear in any Office Online service."
Others impacted include the Teams admin centers, SharePoint Online (users may not be able to view the settings gear, search bar, and waffle), and Planner.
According to DownDetector, reports 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 that the problem was linked to an "unusually high number of timeout exceptions within our caching and our Azure Active Directory (ADD) 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. "We're analyzing forensics within the caching infrastructure to identify the cause of the issue."
According to user reports, some found that when they logged into their Microsoft 365 accounts, they were unable to access the services. One admin in the UK wrote on Reddit that several users reported the problem to them and that they were able to reproduce it in several tenants.
"Same symptoms here across our org (Midwest, US) and a few potentially related tickets with clients this morning," wrote another user. "Thought I was going crazy."
A user from Australia said they experienced similar problems as they tried to install Office apps.
"I disabled and re-enabled the 'Microsoft 365 apps for Business' component of a Business Standard license, then refreshed and all was good," they wrote. "Logged in just now and it looks like the problem's returned."
They then logged into the unlicensed Admin account, "repeated the same disable component, save, re-enabled component, save process – then refreshed the licensed user browser and all appears OK again."
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.
The Register contacted Microsoft and will update the story as more information comes in. ®
Source: The register