Azure Gateway Outage Hit 18 Regions as a Gateway Manager Change Collided With OS Servicing, Microsoft Says
Microsoft says a gateway management service change, combined with unrelated OS servicing, disrupted Azure ExpressRoute and VPN gateways from September 30 to October 1; a post incident review is pending.
Editor's Note ·
- Clarification:
- The headline says the outage "Hit 18 Regions". That figure is The Register's count "at the time of writing" (its article was updated after Microsoft reported mitigation). Microsoft's status history entry 7Q30-010 says only "multiple regions", gives no total, and notes that "Impacted region(s) within a previous communication has been corrected", so the final number of affected regions is not confirmed by Microsoft.
Overview
Microsoft Azure gateway services suffered degraded or interrupted connectivity across multiple regions starting at 20:30 UTC on September 30, 2026. According to Microsoft’s Azure status history (tracking ID 7Q30-010), the impact lasted until 02:15 UTC on October 1, and the company says the trigger was a recent change to a regional gateway management service that interacted with unrelated operating system servicing maintenance. A formal post incident review has not yet been published.
What We Know
- Scope. The Register listed 18 affected regions: West US, West US 3, North Europe, West Europe, France Central, UK West, UK South, Switzerland North, Southeast Asia, East Asia, Japan West, Korea Central, South Africa North, UAE North, Mexico Central, Germany North, South India and Jio India Central. According to The Register, Azure VMware Service was not impacted in the last four of those regions.
- Affected services. Microsoft’s status history names Azure ExpressRoute Gateway, Azure Firewall, Azure Application Gateway and Web Application Firewall, Azure VPN Gateway and Azure VMware Solution. Customers may have observed gateways failing to load in the Azure Portal, along with failures or delays in network management operations, per the status history.
- Cause as stated by Microsoft. The status history says the investigation found that a recent change to a regional gateway management service triggered a higher-than-expected load when an unrelated operating system servicing maintenance proceeded gradually through multiple regions. The service would normally auto scale, but Microsoft says demand on dependent services prevented the regional services from scaling as expected.
- Response timeline. Per the status history, Microsoft began investigating ExpressRoute Gateway connectivity issues in UK South at 21:29 UTC, found the issue was affecting multiple regions at 22:27 UTC, and paused further servicing at 23:05 UTC after identifying a correlation with operating system servicing activity. It reverted the contributing gateway manager change, and confirmed the issue was mitigated at 02:15 UTC on October 1.
- Uneven recovery. At 01:36 UTC, according to the status history, recovery had progressed across most regions while configuration changes were applied to the remaining impacted regions, including France Central, North Europe, Southeast Asia, UK South and UK West. In an earlier update quoted by The Register, Microsoft said that “Some supporting network management components have not recovered automatically and are contributing to management operation failures in a subset of affected regions”.
What We Don’t Know
- Microsoft says it will complete an internal retrospective and, “generally within 14 days”, publish a Post Incident Review to impacted customers, according to the status history. Until then, the scaling behavior and the safeguards against recurrence remain under investigation.
- The sources reviewed do not quantify how many customers were affected or the severity of impact for any individual customer. Microsoft notes that the listed impact times represent the full incident duration and that actual impact may vary between customers and resources.
Analysis
The account in Microsoft’s status history describes an interaction between two separate activities: a service change and a rolling maintenance run that Microsoft characterizes as “unrelated” to it.The Register headlined its report “Azure maintenance mess disrupted hybrid clouds, VPNs, cloudy VMware services” and noted that Microsoft’s investigation continued to show a correlation between the event and infrastructure operating system servicing activity. The company’s final root-cause statement will come with the post incident review.