Users are unable to access Microsoft 365 Copilot Chat or portal.office.com

A post-incident report has been published.

A post-incident report has been published.

Title: Users are unable to access Microsoft 365 Copilot Chat or portal.office.com User impact: Users are unable to access Microsoft 365 Copilot Chat or portal.office.com. More info: Admins may have been able to access the Microsoft 365 admin center via admin.cloud.microsoft as a temporary solution. Additionally, Copilot in Microsoft Teams was not impacted and could have been leveraged in the interim while we mitigated the issue. Final status: We’ve successfully rolled back the change throughout the affected infrastructure, and we've confirmed with previously affected users that the impact is mitigated. Scope of impact: Any user or admin may have been affected by this event. Start time: Thursday, June 11, 2026, at 8:00 PM UTC End time: Thursday, June 11, 2026, at 9:56 PM UTC Preliminary root cause: We've identified an issue with a recent deployment which is contributing to impact. We will provide more information in our Post-Incident Report. Next steps: - We're analyzing the recent deployment to identify why this issue occurred and how to prevent it from happening again in the future. - We're reviewing our change management processes to determine areas of improvement. We'll provide a preliminary Post-Incident Report within two business days and a final Post-Incident Report within five business days.

Title: Users are unable to access Microsoft 365 Copilot Chat or portal.office.com User impact: Users are unable to access Microsoft 365 Copilot Chat or portal.office.com. More info: Admins may be able to access the Microsoft 365 admin center via admin.cloud.microsoft as a temporary solution. Additionally, Copilot in Microsoft Teams is not expected to be impacted and can be leveraged in the interim while we mitigate the issue. Current status: We have successfully reverted the change for 97 percent of the affected infrastructure. We're continuing to monitor the progress of the reversion and we're also observing an uptick in service availability. Additionally, we've started to receive confirmation that service availability is returning for some users. In parallel, we're investigating the underlying cause of the problem and will provide more information when available. Scope of impact: Our investigation indicates that any user or admin may be affected by this event. This section is subject to change as the investigation continues. Start time: Thursday, June 11, 2026, at 8:00 PM UTC Preliminary root cause: We've identified an issue with a recent deployment which is contributing to impact. We will continue to perform a root cause analysis to identify how this occurred and how we can prevent this from happening in the future. Next update by: Thursday, June 11, 2026, at 11:00 PM UTC

Title: Users are unable to access Microsoft 365 Copilot Chat or portal.office.com User impact: Users are unable to access Microsoft 365 Copilot Chat or portal.office.com. More info: Admins may be able to access the Microsoft 365 admin center via admin.cloud.microsoft as a temporary solution. Additionally, Copilot in Microsoft Teams is not expected to be impacted and can be leveraged in the interim while we mitigate the issue. Current status: This is a continuation of a communication posted under CW1387674. We’ve identified an issue with a recent deployment for Microsoft Copilot. We’re reverting to a previous build to remediate impact as soon as possible. We expect this to be completed in the next 30 minutes. Scope of impact: Our investigation indicates that any user or admin may be affected by this event. This section is subject to change as the investigation continues. Start time: Thursday, June 11, 2026, at 8:00 PM UTC Estimated time to resolve: We expect the reversion to be complete in the next 30 minutes. Root cause: The root cause is still being investigated. We will provide more information in our next update. Next update by: Thursday, June 11, 2026, at 10:00 PM UTC