Microsoft Teams Calling Disrupted by Service Incident
Microsoft is investigating a widespread service incident impacting Microsoft Teams calling functionality, preventing some users from making or receiving calls.
Microsoft is currently investigating a significant service incident that is disrupting the calling capabilities of its popular Microsoft Teams collaboration platform. The issue, identified by the reference TM1475580 within the Microsoft 365 admin center, is preventing a subset of users from initiating or receiving voice and video calls.
The company first acknowledged the problem via its official Microsoft 365 Status Twitter account on September 21, 2026. The advisory was notably brief, stating only that "some users" were affected without specifying the scope, affected regions, or a projected resolution timeline. This limited information necessitates careful assessment by IT and security teams to determine the actual impact on their specific environments.
While the incident primarily affects calling functionality, Microsoft has emphasized that other Teams features such as chat, meetings, file sharing, and identity services may remain operational unless local telemetry indicates otherwise. However, for organizations reliant on Teams for critical communications, such as help desks, incident response bridges, and remote worker connectivity, even a partial outage can have significant operational consequences.
Security operations teams are advised to approach affected user reports with caution. A failed Teams call is not inherently indicative of a cyberattack or account compromise; it is more likely linked to the ongoing service-side incident. Nevertheless, it is crucial to correlate user-reported issues with Microsoft's official advisory and to meticulously review network, endpoint, and identity logs to rule out any local network faults or malicious activities.
Microsoft 365 administrators are urged to consult the TM1475580 incident record in their respective admin centers for tenant-specific details and updates. This is the authoritative source for understanding an organization's unique exposure to the outage. Administrators should document key details of reported failures, including user location, client version, call direction, and any error messages encountered, to aid in troubleshooting and potential support case escalation.
During the disruption, organizations should prioritize activating their pre-defined resilient communication plans rather than attempting broad, potentially disruptive configuration changes. Approved alternative communication channels may include Public Switched Telephone Network (PSTN) calling, designated conference bridges, corporate mobile phones, or other sanctioned collaboration tools. It is also a critical time to remind employees to use only approved communication channels for sensitive discussions, as service outages can create opportunities for phishing attempts and unsanctioned data sharing.
Microsoft's investigation into the root cause of the calling issue is ongoing. Administrators are advised to closely monitor the incident record for updates, communicate the confirmed scope of the problem internally, and ensure that any temporary workarounds are discontinued once Microsoft confirms the restoration of normal Teams calling services. The incident underscores the reliance on cloud-based communication tools and the importance of having robust business continuity and disaster recovery plans in place.