Outlook down today: What we know about Microsoft outage hitting email, Teams and 365 worldwide

Microsoft's Outlook email service is facing a major global outage on Friday leaving users unable to access their inboxes, send or receive emails, and use several other Microsoft 365 applications. The disruption, which began on Thursday, has also affected Microsoft Teams, Copilot and other workplace services, disrupting businesses, government offices and educational institutions across multiple countries.

Microsoft has said it is not aware of any malicious activity causing the outage. (AFP/ Representational)The outage appears to stem from a major infrastructure failure involving Microsoft's servers. The company has acknowledged problems with server stability and elevated workloads, but has yet to provide a complete technical explanation of what triggered the disruption.

Importantly, Microsoft has said it is not aware of any malicious activity causing the outage, indicating that there is currently no confirmed evidence of a cyberattack. The disruption has affected users in several countries, with outage-tracking platform Downdetector recording reports from more than 70 countries.

Outlook outage reports in the US peaked at around 138,000 before declining, although users continued to report problems accessing the service. The disruption also affected businesses, government agencies, universities and other institutions dependent on Microsoft's cloud-based services.

The outage is linked to a server-side infrastructure problem involving Microsoft's Exchange Online platform, which powers Outlook's email services. Microsoft's investigation found that a core process on affected servers was becoming overwhelmed.

This caused the servers to stop responding to requests and eventually become unavailable. The problem appears to have triggered a cascading infrastructure failure. As some servers became unavailable after failing automated health checks, the workload shifted to the remaining operational servers.

This increased the pressure on the available infrastructure, contributing to further instability and connectivity problems. Also Read I Microsoft outage: Outlook, Copilot and Teams remain disrupted, over 200,000 user issues reported Microsoft also clarified that the elevated load was not caused by an overall increase in user traffic.

Instead, it was the unexpected unavailability of a large number of servers that created an imbalance across its infrastructure. The company has also been investigating a recent network configuration change that coincided with the beginning of the disruption, while testing alternative configurations to restore server stability.

Microsoft's initial recovery attempts have not produced the expected results. The company tried restarting affected servers, redistributing connection traffic across its global infrastructure and restricting certain types of traffic to reduce pressure on the affected systems.

However, engineers found that some servers which had been brought back online became unresponsive again once traffic was redirected to them. This complicated efforts to restore services and meant that recovery had to be approached gradually.

Microsoft subsequently acknowledged that its changes to improve service availability were not working as expected and said it was exploring alternative ways to increase capacity and stabilise the infrastructure. Microsoft has said it is not aware of any malicious activity causing the disruption.

The company has explicitly said there is no indication of a cyberattack or malicious activity behind the incident. Its investigation has instead focused on server availability, authentication and routing-related infrastructure problems.

Microsoft has promised to publish a detailed post-incident report once the disruption is fully resolved. The report is expected to explain the root cause and the additional measures being taken to prevent similar incidents.