Microsoft's push to move customers off Office 2021 LTSC hit an awkward snag this week when a Microsoft 365 outage disrupted services for some European users. The problem was traced to Global Secure Access (GSA), a piece of infrastructure that fronts access to Outlook, OneDrive, SharePoint Online, Teams, and Windows 365 Cloud PCs. Microsoft said a section of GSA infrastructure was performing below acceptable thresholds, and it was applying traffic and performance optimizations.
The timing was particularly unfortunate because October 13, 2026, marked the end of support for Office LTSC 2021, Microsoft's on-premises productivity suite. The company has long encouraged customers to move to Microsoft 365, but it also still sells Office LTSC 2024 for those who prefer to stay on-premises. The outage gives cloud skeptics another data point, though Microsoft has not yet disclosed the root cause.
Adding to the frustration, Microsoft's Service Health Status page was itself affected. The company noted that administrators might be unable to access the admin center to get service health information, and a check of the status page showed a warning that incident details were temporarily unavailable. For enterprises that have already committed to Microsoft 365, the incident underscores the risk of relying on cloud services for critical productivity workloads, even as the end of support for Office 2021 LTSC forces some compliance-driven decisions.