User impact: Some users may be unable to view or access Microsoft 365 apps or services

More info: Impacted services may include but are not limited to:
– Microsoft 365 Online apps – Users may be unable to access Microsoft 365 web apps, such as Excel Online. Additionally, the search bar may not appear in any Office Online service.
– Microsoft Teams – Users may be unable to access the Microsoft Teams admin center.
– SharePoint Online – Users may be unable to view the settings gear, search bar and waffle.
– Microsoft Planner – Users may be unable to access Microsoft 365 web apps through Microsoft Planner.

Current status: 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. We’re analyzing forensics within the caching infrastructure to identify the cause of the issue.

Scope of impact: Impact is specific to some users who are served through the affected infrastructure.

Start time: Thursday, April 20, 2023, at 12:38 AM UTC

Next update: Thursday, April 20, 2023, at 4:30 PM UTC

Root cause: 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.