Microsoft incident · via Microsoft 365 (Business or Enterprise)
Users in the United States and United Kingdom may be unable to access Microsoft 365 services
Microsoft experienced a minor incident on September 16, 2026, lasting 4h 59m. The incident has been resolved; the full update timeline is below.
Update timeline
- monitoring Sep 16, 2026, 02:29 PM UTC
Title: Some users in the United States and United Kingdom may be unable to access Microsoft 365 services User impact: Users in the United States and United Kingdom may be unable to access Microsoft 365 services. Current status: We're reviewing service monitoring telemetry and associated reports to isolate the root cause, in order to develop a remediation plan. Scope of impact: Impact is specific to users in the United States and United Kingdom attempting to access Microsoft 365 services. This information may be updated as our investigation continues. Next update by: Wednesday, September 16, 2026, at 3:30 PM UTC
- monitoring Sep 16, 2026, 02:35 PM UTC
Title: Some users in the United States and United Kingdom may be unable to access Microsoft 365 services User impact: Users in the United States and United Kingdom may be unable to access Microsoft 365 services. Current status: We're reviewing service telemetry while investigating reports of users encountering 502 and 503 errors when accessing Microsoft 365 services. Recent user reports indicate the impact may be decreasing and we're continuing to analyze service health data to determine whether service conditions are improving and to isolate the source of impact. Scope of impact: Impact is specific to users attempting to access Microsoft 365 services and users whose service requests are routed through the United States and United Kingdom regions. This information may be updated as our investigation continues. Next update by: Wednesday, September 16, 2026, at 3:30 PM UTC
- monitoring Sep 16, 2026, 03:15 PM UTC
Title: Some users in the United States and United Kingdom may be unable to access Microsoft 365 services User impact: Users in the United States and United Kingdom may be unable to access Microsoft 365 services. More info: Impacted users may encounter 502 or 503 errors when attempting to access Microsoft 365 services. Current status: Our investigation remains focused on the cause of the Single Sign-On (SSO) failures and associated 5xx errors. In parallel, we're reviewing upstream dependencies to determine whether they are contributing to the impact. While some affected customers have reported improvement in service availability, our investigation continues as we work towards a full resolution. Start time: Wednesday, September 16, 2026, at 1:22 PM UTC Next update by: Wednesday, September 16, 2026, at 4:30 PM UTC
- monitoring Sep 16, 2026, 04:47 PM UTC
Title: Some users in the United States and United Kingdom may be unable to access Microsoft 365 services User impact: Users in the United States and United Kingdom may be unable to access Microsoft 365 services. More info: Impacted users may encounter 502 or 503 errors when attempting to access Microsoft 365 services. Current status: Impact reports continue to decrease. Our investigation has not identified any issues with core Microsoft 365 components. As part of our ongoing root cause analysis, we're focusing on the request paths and dependency conditions associated with the reported Single Sign-On (SSO) failures and 5xx errors, while continuing to monitor and confirm sustained recovery. Start time: Wednesday, September 16, 2026, at 1:22 PM UTC Next update by: Wednesday, September 16, 2026, at 5:30 PM UTC
- monitoring Sep 16, 2026, 05:59 PM UTC
Title: Some users in the United States and United Kingdom may be unable to access Microsoft 365 services User impact: Users in the United States and United Kingdom may be unable to access Microsoft 365 services. More info: Impacted users may encounter 502 or 503 errors when attempting to access Microsoft 365 services. Current status: Impact reports have largely subsided, and service telemetry continues to indicate stable service conditions. Our investigation hasn’t identified a corresponding issue within the Microsoft 365 service environment, and we’re assessing whether conditions outside the core service path contributed to the reported impact. We’re continuing to monitor service health and validate sustained recovery. Start time: Wednesday, September 16, 2026, at 1:22 PM UTC Next update by: Wednesday, September 16, 2026, at 6:30 PM UTC