Microsoft has said its outage still cannot be fixed and the exact cause remains unclear in a new statement. The tech giant issued a key update on the cause of a major outage affecting users worldwide, impacting Teams, Outlook and Copilot.
In the latest statement just after 4am UK time, Microsoft said: "As part of our investigation into the sustained traffic management imbalances, we're reviewing traffic flows and affected infrastructure to identify opportunities to optimize routing."
"This includes verifying the reasons for service failures so we can develop specific actions to improve stability."
Outage Causes and Impact
The tech giant has been suffering the major outage for several hours now, saying that it is "aggressively pursuing" methods to fix the problem. The outage is affecting several Microsoft Suite platforms, including Outlook emails, messaging platform Teams, and the AI assistant Copilot.
Industries from health services and hospitals, to AI providers, to cybersecurity firms are being affected.
A later update said the problem was caused by a "large number" of servers being made "unexpectedly unavailable". Microsoft then said it was able to get a "subset" of servers back online and was working to apply those changes more broadly.
Microsoft's Response and Investigation
The tech titan has explained: "While we haven't identified any recent changes that correlate with the start of impact, our investigation indicates the failed health checks may originate from a specific component on the affected servers that's responsible for processing them."
"We're deploying a targeted change to bypass this component on a subset of servers to validate whether this restores availability, and we've taken steps to prevent additional servers from being removed from service while we work to return the affected servers to service."
"We're also investigating why affected servers are experiencing elevated processor usage while handling requests."
User Reports and Affected Services
More than 3,000 UK users reported issues on outage tracker Downdetector shortly after 6pm, with the majority struggling to log in to their accounts. In the US, almost 130,000 people have been affected. Reports have fallen since that peak, but many users continue to complain of being unable to send or receive emails, while others are struggling to load their inboxes altogether.
As problems continued, leaving workers globally twiddling their thumbs, Microsoft reported at around 2am UK time: "We're seeing positive results with our efforts to restart affected infrastructure."
But just under 30 minutes later, Microsoft was less positive, saying: "We're applying infrastructure capacity improvements where possible in an effort to help support traffic in regions coming online. We're continuing to monitor the results of changes applied so we can identify strategic actions that can help to improve service health across all affected regions."
The list of services which are currently down has been posted on the Microsoft website, and has grown significantly as the hours have worn on.
Microsoft says features that interact with Exchange Online and email services are impacted. Microsoft says there are some elements of services that don't rely on interactions with Exchange Online which are functional.
