Microsoft has confirmed that a significant service disruption affecting Outlook and Microsoft 365 is currently underway, with the company attributing the instability to a recently introduced change. The outage, which began early Monday morning, April 27, 2026, has left enterprise and business customers struggling to log in to their mailboxes and essential productivity tools.
Addressing the Microsoft 365 Service Degradation
According to reports from BleepingComputer, the disruption has been classified by Microsoft as a service degradation incident. Users began reporting widespread issues around 5:00 AM ET, with many encountering persistent login failures and error messages citing “too many requests.” The impact has been particularly disruptive for global teams starting their work week, as users are frequently experiencing unexpected sign-outs and an inability to connect to their accounts via web and desktop clients.
The Cause Behind the Microsoft Outage
In a formal update provided during the morning hours, Microsoft stated that they are in the process of reverting a specific configuration change to determine if it resolves the ongoing connectivity issues. While the company has not disclosed the exact nature of the change or the full geographic scope of the impact, they confirmed that the primary symptom is intermittent sign-in failure. Windows Central noted that the company is actively analyzing service telemetry to guide further mitigation actions.
Ongoing Impact on Outlook Users
This incident follows a series of stability challenges for Microsoft’s enterprise suite, including recent disruptions involving Exchange Online and Copilot services. While the current outage does not appear to have taken the platform completely offline for all users, the volume of reports on platforms like Downdetector suggests a substantial portion of the user base is currently unable to access their email. Microsoft continues to provide updates through their official 365 status channels as they work toward a full restoration of services.
The frequency of these service interruptions highlights the fragility of integrated cloud-based ecosystems, where a single deployment can trigger cascading authentication failures across global business operations.