We have reports from clients that some users 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 improved service availability, our investigation continues as we work toward a full resolution.
The M3TC team is aware of this issue and is keeping an eye on it for any impact or remedy requirements
Start time: Wednesday, September 16, 2026, at 1:22 PM UTC
More on this Service Advisory can be found by clicking here
