Microsoft Hit by Dual Cloud Outages on June 1-2, 2026

On June 1-2, 2026, Microsoft's cloud services were hit by a pair of simultaneous but separate disruptions that locked users out of critical workflows. Incident MO1329446 prevented users from opening files in Office for the web and Microsoft Teams, while incident MO1329260 blocked access to the My Sign-Ins portal, making it impossible to set up multi-factor authentication (MFA). Neither incident has a published post-mortem yet, but the available status updates and industry tracking paint a clear picture of the immediate impact and the broader reliability concerns plaguing Microsoft's cloud in 2026.

Inside MO1329446: Office for the Web and Teams File Access Collapses

Starting on June 1, users attempting to open Excel, PowerPoint, or other files within Office for the web or directly in Microsoft Teams were met with a blunt error message: "Office Online service is currently unavailable. We're working to restore all services as quickly as possible" . Microsoft confirmed the disruption was a "cross-service issue affecting the Office for the web experience," indicating the problem was not contained within a single application but spanned multiple dependent backend systems .

The company's telemetry detected a sharp increase in error rates across Office web apps, and its engineers began correlating those patterns across service dependencies to identify a fix . The incident was resolved around 12:48 UTC on June 2 .

Because Microsoft has not released a final root-cause analysis (RCA), the precise engineering trigger remains unconfirmed. However, the "cross-service" characterization strongly suggests a shared backend dependency—such as a storage, authentication, or session-management layer used by both Teams and the Office web apps—failed, cascading into the user-facing error .

Inside MO1329260: MFA Setup Portal Returns 504 Errors

Concurrently, a separate incident was unfolding for users attempting to configure multi-factor authentication. When navigating to the My Sign-Ins portal (mysignins.microsoft.com), users received 504 Gateway Timeout errors, effectively blocking the ability to set up MFA for new accounts or manage existing methods . The incident lasted approximately 3 hours on June 1 .

Microsoft's mitigation strategy involved failing over to alternate, healthy infrastructure to restore service . The 504 error pattern and the need for an infrastructure failover point to a failure in the backend service or load-balancing layer that fronts the authentication portal.

It is worth noting that this is not the first MFA-related outage in 2026. A February incident (MO1237461) caused similar 504 errors for MFA sign-ins and was later tied to a third-party MFA provider, Duo, which deployed a fix on its end . Microsoft has not yet disclosed whether MO1329260 involved a similar third-party dependency or was a purely first-party Entra ID service failure.

A Troubling 2026 Trajectory: Now Five Major Outages in Six Months

These two June incidents are not outliers. They are the latest data points in an unusually dense cluster of high-impact cloud outages for Microsoft in 2026. Industry trackers have now logged five significant events in the first half of the year .

Major Microsoft Cloud Outages: Oct 2025 – June 2026

• October 2025: An Azure Front Door DNS failure caused broad service degradation across Microsoft 365 and Azure .
• January 22-23, 2026: A combination of Azure infrastructure issues and a third-party networking failure triggered a ~9.5-hour outage, taking down Outlook, Exchange, Teams, Defender, and Purview. The incident alone broke Microsoft's annual uptime commitment for several workloads .
• February 2026: An MFA outage (MO1237461) caused 504 Gateway Timeout errors for North American users. Microsoft confirmed it was mitigated by a fix from a third-party MFA provider .
• April 2026: A widespread cloud disruption caused connectivity issues across multiple regions, affecting Teams, Outlook, and Azure .
• June 1-2, 2026: The dual incidents MO1329446 (file access) and MO1329260 (MFA setup) occurred simultaneously, blocking two distinct but critical service areas .

Recurring Failure Patterns

Several uncomfortable themes have emerged from this string of incidents:

• Third-Party Dependency Risk: The January megafailure and the February MFA outage were both linked to third-party networking or service providers. This recurring pattern raises serious questions about Microsoft's dependency management architecture, failover testing, and visibility into its supply chain's reliability .
• Identity Layer Fragility: MFA and authentication portals have become a concentrated point of failure. With at least three identity-related incidents in 2026 alone, the very system designed to secure access has become an access barrier itself .
• Cross-Service Blast Radius: The "cross-service" nature of MO1329446 echoes the January catastrophe, where a single infrastructure fault cascaded into simultaneous failures across email, collaboration, security, and compliance tools. This pattern of concentrated systemic risk in a highly centralized cloud architecture is a growing concern for enterprise customers .
• Eroded SLA Confidence: The January 9.5-hour outage already pushed Microsoft past its financial-backed uptime guarantees for key services . Each subsequent incident further erodes customer trust that the company can maintain the reliability its service-level agreements promise.

The Post-Mortem Question

The critical caveat for both June incidents is the absence of formal RCAs. All analysis above is based on Microsoft's real-time status messaging, admin center updates, and third-party outage tracking. Until Microsoft publishes detailed engineering post-mortems, it remains impossible to determine if these two events shared a common underlying trigger—such as a single infrastructure change that degraded two separate services—or if they were simply an unlucky coincidence. What is already clear, however, is that they fit a broader and deeply concerning 2026 trend that has the enterprise IT world on alert.