Microsoft has confirmed that some users in Japan are experiencing problems with Microsoft 365 services and the AI-powered Copilot assistant. The disruptions have affected sign-ins and access to Microsoft 365 tools, prompting the company to investigate the issue and provide updates through its service health channels.
The alert appears under incident MO1198797 in the Microsoft 365 admin portal, where Microsoft posts details about ongoing service issues for administrators. The company has advised users and IT teams in Japan to monitor this portal for the latest status and guidance while the investigation continues.
What Happened and Where Users Are Affected
Reports show that users in Japan and in some cases neighboring regions have faced trouble accessing core Microsoft 365 apps. These include services like Outlook, Teams, OneDrive, and the integrated AI features in Copilot. Users may have encountered slow load times, sign-in failures, or limited functionality during the issue.
The problem was flagged on December 18, 2025, and the disruption appeared to start around midnight UTC (8:00 AM JST) when a portion of the service infrastructure handling traffic in Japan became unhealthy due to a routing issue. That meant normal connections couldn’t be established for some users trying to access their accounts or use Copilot commands.
How Microsoft Is Responding
Microsoft’s engineering teams responded quickly after the alerts began. Company officials updated the Microsoft 365 status page and the admin portal, acknowledging the issue and confirming they were actively analyzing service telemetry and user reports.
However, in the initial stages of the investigation, Microsoft had not yet shared detailed technical explanations for the root cause or a full timeline for when services would be fully restored. The company has said it will release additional updates as the investigation continues and more information becomes available.
Confirmed Outage and Restoration for Some Users
While Microsoft’s internal admin portal showed the issue being investigated, service tracking sites and reports from users in Japan and China indicate that many of the affected services were later restored following mitigation efforts. Engineers took steps to rebalance traffic across healthy infrastructure to restore availability and normalize operations.
The outage impacted access and sign-in across multiple Microsoft 365 apps, leading many businesses and individuals who rely on cloud collaboration tools to experience delays and hiccups in productivity during the disruption.
Why This Matters to Users
Microsoft 365 is a cornerstone tool for many companies, schools, and organizations in Asia and around the world. When services like Outlook (for email), Teams (for collaboration), OneDrive (for file storage), and Copilot (for AI-enhanced productivity) encounter outages, it can interfere with daily work, remote operations, and customer support workflows.
Copilot, in particular, uses artificial intelligence to help users summarize content, draft text, analyze data, and automate tasks. Interruptions to Copilot can affect workflows that depend on its AI features, especially for teams that use the assistant for productivity gains.
What Users Experienced During the Outage
During the peak of the disruption, many Microsoft 365 users in the impacted regions reported:
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Login problems when trying to access their accounts
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Difficulty using Copilot for AI-driven tasks
These issues led some organizations to switch temporarily to alternative communication or productivity tools while Microsoft worked on restoring services.
Microsoft’s Official Guidance
Microsoft has advised administrators and users in Japan and nearby regions to:
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Check the Microsoft 365 admin center for the latest updates
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Follow messages under incident MO1198797 for ongoing status
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Monitor service health reports as engineering teams work toward resolution
These updates provide real-time information about the scope of service impact, steps taken to mitigate problems, and any recommended actions for IT teams.
Common Causes of Outages Like This
Technical disruptions to cloud services can stem from many sources. In this case, early reports point to a routing item in Microsoft’s infrastructure that made parts of the network unhealthy, blocking successful connections for users. Similar issues can occur when:
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Traffic distribution systems struggle to direct users to the right infrastructure
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Network misconfigurations cause certain servers to become unreachable
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Regional data center components encounter errors that affect access
These kinds of problems are separate from cyberattacks and usually relate to internal routing and server performance.
Looking Ahead: Monitoring and Prevention
Microsoft will likely continue to monitor infrastructure logs, performance telemetry, and user reports to understand what exactly caused the issue and prevent similar disruptions in the future. The company often follows outages with internal reviews and possible infrastructure adjustments.
For users, staying updated through official status messages and admin portal alerts is the best way to track the progress of service restoration and get alerts when issues are resolved.
Conclusion
A network-related issue disrupted Microsoft 365 and Copilot services for many users in Japan and nearby regions, affecting key productivity apps and AI functionality. Microsoft has responded with internal investigations and status updates, and many services have since been restored. Users and IT teams should continue to watch official channels for ongoing updates as engineers work to fully resolve the problem.