Live status of all services Incident · resolved

Some users may have been unable to send messages in Microsoft 365 Copilot chat

Microsoft 365 Copilot Chat CW1515013

Users may have been unable to send messages in Copilot chat.

Status
Service restored
Feature
General
Region
Not specified (all regions)
Started
Oct 19, 2026, 11:27 CEST
Resolved
Oct 19, 2026, 12:21 CEST
Duration
53 min

More info

Impacted experiences included Copilot chat through the Copilot web app, the Copilot app on Windows, Microsoft Teams, Outlook, and Microsoft 365 desktop apps.

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 may have been impacted.

Root cause

A recent Copilot service update inadvertently increased traffic beyond expected levels, resulting in impact.

Next steps:
- We're reviewing our update procedures to better identify similar issues during our development and testing cycles.

This is the final update for the event.

Final status

We’ve determined that a recent Copilot service update inadvertently increased traffic beyond expected levels, resulting in impact. We’ve confirmed that reverting the update successfully mitigated the impact and restored the service.

Timeline

Every update Microsoft posted for this issue, newest first.

  1. Oct 19, 2026, 12:23 CEST

    We’ve determined that a recent Copilot service update inadvertently increased traffic beyond expected levels, resulting in impact. We’ve confirmed that reverting the update successfully mitigated the impact and restored the service.

  2. Oct 19, 2026, 11:29 CEST

    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.

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To see whether your own tenant is affected, check Service health in the Microsoft 365 admin center. Only a backup outside Microsoft protects against data loss, and only a tested break-glass account against locked-out admins. We set up both in fixed-scope sprints.

Source: Microsoft Graph, Service Communications API. This is the view of a Swiss Microsoft 365 tenant: services not licensed there are missing, and individual issues may affect your tenant differently. Microsoft names the region only in the issue text. The Switzerland view shows issues for Switzerland, for Europe in general and those without a region, but not issues that only name other countries such as Germany or the UK. This page is not provided by Microsoft.