Outage in Microsoft 365
Some users may be unable to send messages in Microsoft 365 Copilot chat
Resolved Minor
October 19, 2026 - Started 1 day ago
- Lasted about 1 hour
Incident Report
Summary AI Generated
Some users were unable to send messages in Microsoft 365 Copilot chat across multiple surfaces, including the Copilot web app, Windows app, Teams, Outlook, and Microsoft 365 desktop apps. The issue was traced to underperforming Copilot service infrastructure, with a recent service change identified as a likely contributor. Microsoft reverted the change as a mitigation measure while continuing to analyze telemetry to confirm the root cause.
Title: Some users may be unable to send messages in Microsoft 365 Copilot chat
User impact: Users may be unable to send messages in Copilot chat.
More info: Impacted experiences include Copilot chat through the Copilot web app, the Copilot app on Windows, Microsoft Teams, Outlook, and Microsoft 365 desktop apps.
Current status: We’ve identified that a section of the Copilot service infrastructure that facilitates access is performing below acceptable thresholds. We’ve identified a service change that may be contributing to the impact and have reverted the change in an attempt to mitigate the issue. In parallel, we’re reviewing service telemetry and error data to confirm the root cause.
Scope of impact: Some users attempting to send messages in Copilot chat through the Copilot web app, the Copilot app on Windows, Microsoft Teams, Outlook, and Microsoft 365 desktop apps are impacted. This information may be updated as our investigation continues.
Next update by: Monday, October 19, 2026, at 11:30 AM UTC
User impact: Users may be unable to send messages in Copilot chat.
More info: Impacted experiences include Copilot chat through the Copilot web app, the Copilot app on Windows, Microsoft Teams, Outlook, and Microsoft 365 desktop apps.
Current status: We’ve identified that a section of the Copilot service infrastructure that facilitates access is performing below acceptable thresholds. We’ve identified a service change that may be contributing to the impact and have reverted the change in an attempt to mitigate the issue. In parallel, we’re reviewing service telemetry and error data to confirm the root cause.
Scope of impact: Some users attempting to send messages in Copilot chat through the Copilot web app, the Copilot app on Windows, Microsoft Teams, Outlook, and Microsoft 365 desktop apps are impacted. This information may be updated as our investigation continues.
Next update by: Monday, October 19, 2026, at 11:30 AM UTC
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Latest Updates ( sorted recent to last )
1 day ago - at 10/19/2026 09:29AM
Title: Some users may be unable to send messages in Microsoft 365 Copilot chat
User impact: Users may be unable to send messages in Copilot chat.
More info: Impacted experiences include Copilot chat through the Copilot web app, the Copilot app on Windows, Microsoft Teams, Outlook, and Microsoft 365 desktop apps.
Current status: We’ve identified that a section of the Copilot service infrastructure that facilitates access is performing below acceptable thresholds. We’ve identified a service change that may be contributing to the impact and have reverted the change in an attempt to mitigate the issue. In parallel, we’re reviewing service telemetry and error data to confirm the root cause.
Scope of impact: Some users attempting to send messages in Copilot chat through the Copilot web app, the Copilot app on Windows, Microsoft Teams, Outlook, and Microsoft 365 desktop apps are impacted. This information may be updated as our investigation continues.
Next update by: Monday, October 19, 2026, at 11:30 AM UTC
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