ACTIVE – DNS Resolution Issues for Azure Domains via Cisco Umbrella (OpenDNS)

Customers using Cisco Umbrella (OpenDNS) experienced DNS resolution issues when accessing portal.azure.com and other Azure services. The issue was confirmed to be an external (Cisco Umbrella) DNS service provider issue. Customers were able to restore connectivity by using an alternate DNS resolver during the issue. Cisco Umbrella subsequently fixed the issue. Our monitoring is seeing recovery as well. Impact start time: 10:55 UTC, 30 December 2025. Impacted region: Global. Our Engineering teams continue to investigate. We will provide updates as the situation evolves.