Cisco Umbrella customers with DNS policies configured to block the "M365 Copilot" or "Microsoft Copilot" application categories should no longer experience related access issues with Microsoft 365 services.
Customers who applied the previously provided workaround can review and restore their DNS policy settings as appropriate for their organization’s security requirements.
Thank you for your patience. If you continue to experience issues, please contact Cisco Customer Support.
Posted Jul 25, 2026 - 21:09 UTC
Identified
We have identified the issue and are currently mitigating the impact.
The previously provided workaround remains available for customers experiencing access issues with Microsoft 365 services. Customers may temporarily remove or allow the "M365 Copilot" and "Microsoft Copilot" application category blocks in their DNS policy, after reviewing the change against their organization’s security requirements.
Updates and additional details will be provided as new information becomes available.
Posted Jul 25, 2026 - 16:48 UTC
Investigating
We are investigating an issue affecting Cisco Umbrella customers with DNS policies configured to block the "M365 Copilot" and "Microsoft Copilot" application categories.
Affected customers may experience access issues with some Microsoft 365 services, including Outlook and Office applications, where related Microsoft hostnames may be matched to these Copilot application categories and blocked by policy.
As a workaround, customers experiencing this issue can temporarily remove or allow the "M365 Copilot" and "Microsoft Copilot" application category blocks in their DNS policy. Customers should review any policy changes against their organization’s security requirements.
Our engineering teams are actively investigating. Updates and additional details will be provided as new information becomes available.
We appreciate your patience and understanding during this time.