Nearly 130,000 users worldwide reported problems accessing Microsoft Corp. (NASDAQ: MSFT) services on Thursday, as the tech giant confirmed connectivity issues across multiple regions.
The outage hit key enterprise tools including Microsoft 365, Teams, and Outlook, leaving workplaces scrambling. According to the BBC, monitoring website Downdetector recorded a sharp spike in complaints as users across the UK and the US experienced widespread disruptions.
We're returning a portion of affected servers to the service, and they remain stable so far. We're also shifting traffic to alternate routes wherever possible and observing limited recovery. In parallel, we've streamlined the process of returning the remaining affected servers to…
Microsoft initially said that the elevated infrastructure load was concentrated in the Americas. Subsequent updates, however, confirmed that the errors could affect users in any region, with software such as Copilot and OneDrive also impacted.
Server Health Check Failures Disrupted Productivity Suites
- Infrastructure Strain: The disruption stemmed from a server health check failure rather than an influx of incoming user traffic.
- Service Disruption: Core productivity suites including Exchange Online, SharePoint, and Teams faced severe accessibility hurdles globally.
- Mitigation Steps: Engineers paused all ongoing deployments and initiated automated server restarts to clear backlogs.
Server Availability Failures Strained Global Infrastructure
The core issue did not stem from a sudden surge in global network traffic. Instead, Microsoft discovered that a group of servers had unexpectedly become unavailable after failing automated health checks.
We determined the elevated load isn't driven by an increase in traffic, but by a number of servers being unexpectedly unavailable; straining the remaining infrastructure. We're working to safely return them to service. More info under EX1550543 and MO1550821 in the Microsoft 365…
This failure placed severe strain on the remaining infrastructure.
The resulting bottleneck disrupted connection methods for enterprise mailboxes and collaboration tools. First responders and public agencies, including Portland Fire & Rescue in Oregon, noted potential delays in processing incoming electronic communications.
We're investigating reports of users experiencing issues accessing Exchange Online mailboxes through multiple connection methods in the Americas. More details can be found in the Microsoft 365 admin center under EX1550543.
Engineers Paused Configuration Changes to Restore Stability
As the disruption extended into the evening hours, Microsoft engineers worked to restore stability. Initial attempts to route traffic away from the affected infrastructure failed to provide the anticipated relief.
“We’re opening all available pathways to restore service, as our actions taken thus far have not provided the anticipated relief,” Microsoft said in an update shared via Mashable.
To isolate the root cause, engineers paused all configuration changes and deployment updates. By late Thursday evening, the company reported success in validating an alternative health check method on a subset of affected servers, allowing teams to begin returning them to active service.
“In parallel, we've streamlined the process of returning the remaining affected servers to service,” Microsoft wrote in an update on X.
We've validated an alternative service health check method, which allowed a subset of affected servers to successfully return to service. We're now applying this change more broadly. We're also preparing automated recovery systems to continually detect and restart unresponsive…
| Service Impacted | Reported Issues | Primary Region |
|---|---|---|
| Microsoft Outlook | Over 131,000 Down Detector reports | Global |
| Microsoft Teams | Connectivity errors and dropped calls | Americas, Europe |
| Microsoft 365 Suite | Authentication and loading failures | Multi-region |
Broader Ecosystem Fallout
The connectivity failure rippled beyond Microsoft’s proprietary ecosystem, affecting third-party platforms reliant on its APIs. Both OpenAI and Anthropic confirmed that the service interruption affected the Microsoft 365 connector linking ChatGPT and Claude AI tools to enterprise storage.
Businesses heavily reliant on cloud infrastructure faced temporary halts in daily workflows.
We’re opening all available pathways to restore service, as our actions taken thus far have not provided the anticipated relief. We found a core process on affected servers is becoming overwhelmed, causing capacity loss. To validate a potential recovery, we're isolating a portion…
Microsoft continued to monitor server health as automated restart scripts cleared out unresponsive components. Further updates regarding full system recovery are expected as the remaining infrastructure finishes cycling through diagnostic checks.
Disclaimer: The information provided in this article is for educational and informational purposes only and does not constitute financial advice.
If you're having trouble accessing some Microsoft services like Outlook, OneDrive, or Copilot … yeah, a thing is going ATM.https://t.co/uyxit6UcWG
More on Outlook
AGGIE ALERT – Microsoft is investigating issues affecting Microsoft 365 services today. UC Davis campus community members may experience issues using MS Outlook, Office web apps, SharePoint, Teams & other services. For resources and more information: https://t.co/41wyZiw6hX
Microsoft Outlook is down. Microsoft 365 issues are cutting people off from their email, as well as Microsoft Teams, SharePoint Online, and Microsoft 365 Copilot https://t.co/4odaKBRKQS
