Massive Tech Failure Hits Global Services as Microsoft Servers Suffer Heavy Strain

UPDATE - follow-up to What we know about the global Microsoft outage: Microsoft services including Outlook, Teams, and Copilot suffered connectivity problems in a massive global outage that lasted more than 20 hours.

Affected Services

Over 430 million people use Microsoft 365 apps. Monitoring website Downdetector recorded 140,000 people from 74 countries reporting issues with Outlook on Thursday evening. Tech companies OpenAI and Anthropic also reported problems connected to Microsoft's services.

Global Impact

Schools, pharmacies, and police forces across the UK were affected, with some GP surgeries asking patients not to send website messages. In the US, courts from Los Angeles to Texas warned of delayed communications, and city governments faced disruptions. Canadian healthcare networks in Toronto experienced email issues, while Japan's shared IT platform was also disrupted.

Cause And Recovery

Microsoft ruled out a cyber-security incident and blamed the issue on elevated load on its infrastructure. A large number of servers became unexpectedly unavailable, which sent extra traffic to the remaining servers. Prof James Ferryman from the University of Reading noted that the servers responsible for setting up secure connections got swamped and stopped answering, causing the failure to snowball. Microsoft later reported encouraging recovery progress in Europe and North America, with email queues approaching normal levels.

Context

Cloud-based services rely heavily on vast networks of connected servers to handle daily digital communication and data storage for millions of users worldwide. When a major technical failure hits central infrastructure, it creates a ripple effect across multiple vital public and private sectors at the same time.