Cloud-Probleme: Stundenlange Ausfälle bei Microsoft 365

A nationwide outage plunged many businesses and consumers into disruption of critical cloud services provided by Microsoft. The disruption extended beyond the email service Outlook, affecting numerous offerings within the Microsoft 365 package. For instance, the office communication platform Teams malfunctioned when scheduling meetings and linking calendars.

Moreover, the AI assistant Copilot, the administration portal for administrators, and interfaces with third-party providers - including AI services like OpenAI and Anthropic - were intermittently disrupted. Microsoft documented the battle against the failures through announcements on its online platform X and its service status page, initially without achieving a breakthrough.

After initial reports of issues with Exchange Mailboxes in the United States, the corporation warned that the disruption could impact connectivity to Microsoft 365 services globally. Microsoft provided no hints of a cyberattack. According to Microsoft engineers, an overburdened process on affected servers responsible for establishing secure connections was the root cause, leading to the computers ceasing to process requests.

Additionally, the company reversed a recent configuration change that occurred around the same time the outage began. At times, Microsoft seemed to have achieved success: a fraction of servers were brought back online - "and they remain stable for now." However, the setback followed: endangered servers threatened to go down again as soon as data traffic hit them.

Even a later attempt to isolate parts of the infrastructure resulted in only partial positive outcomes, according to corporate statements. Microsoft revealed that they were seeking alternative ways to increase capacities amid ongoing imbalances in data traffic control. When all Microsoft 365 services would run uninterrupted again remained unclear.

Outages of online services are common, but sometimes the problems in the huge cloud infrastructures are so severe that they cause hours-long disruptions. Microsoft's cloud and email services had already experienced a nationwide large-scale outage in late August, during which users could not log in or send and receive messages for hours.