The disruption also affected connectors powering AI services from OpenAI and Anthropic.
Microsoft 365, Outlook, Teams and other company applications remained disrupted for thousands of users for more than five hours on Thursday. The outage also affected connectors used by AI services from OpenAI and Anthropic.
As of 6pm ET, Microsoft said it was continuing efforts to restore affected servers, with limited recovery observed as users gradually reconnected. Reports of Outlook issues peaked at 138,058 at around 1pm ET before dropping to approximately 34,490 by the evening, according to Downdetector.
Earlier in the day, Microsoft attributed the disruption to several servers becoming unexpectedly unavailable under the existing workload, rather than a surge in traffic.
“We are aware and investigating reports of users experiencing issues with Microsoft 365 services, primarily issues with Exchange Online,” a Microsoft spokesperson said.
By 5.47pm ET, reports of Microsoft 365 problems had fallen to nearly 13,000, while 763 users had reported difficulties accessing Teams, according to Downdetector.
The technology giant said servers that had been restored were continuing to operate stably. It was also redirecting traffic through alternative routes where possible and working to speed up the restoration of the remaining affected servers.
“As capacity is restored, users may experience a gradual recovery as their clients reconnect,” Microsoft said in a statement.
Businesses feel the impact
The disruption extended beyond Microsoft’s own applications, affecting third-party services that rely on its connectors.
OpenAI said it was investigating an issue with Microsoft connectors that could cause new connections to fail and prevent tools from working as expected.
Anthropic also said it had identified a problem with an upstream provider affecting its Microsoft 365 connector.
Last month, Microsoft reported an outage involving its Azure cloud platform, which affected its productivity software suite and disrupted services across several industries worldwide.
The latest disruption also had business consequences. Electric truck maker Workhorse Group, which was scheduled to announce its third-quarter results on November 12, postponed the announcement to November 16, citing business disruptions caused by the global Microsoft outage.
