Back to All Scenarios
PASSEDvoip / teams_calling_outage
Microsoft Teams Calling Outage — Enterprise Voice Down
Microsoft Teams Phone System experiences a regional outage affecting all Teams calling features. Users cannot make or receive PSTN calls through Teams. Direct Routing SBC shows the Teams backend as unreachable. Internal Teams chat and meetings work but all telephony features are offline.
Pattern
AZURE_CLOUD
Severity
CRITICAL
Confidence
85%
Remediation
Remote Hands
Test Results
| Metric | Expected | Actual | Result |
|---|---|---|---|
| Pattern Recognition | AZURE_CLOUD | AZURE_CLOUD | |
| Severity Assessment | CRITICAL | CRITICAL | |
| Incident Correlation | Yes | 35 linked | |
| Cascade Escalation | Yes | Yes | |
| Remediation | — | Remote Hands — Corax contacts on-site support via call, email, or API |
Scenario Conditions
Microsoft Teams Phone System with Direct Routing. 500 Teams voice users. Azure region East US 2 experiencing degraded services. SBC cannot register with Teams backend. PSTN calling completely offline. Teams chat/meetings unaffected.
Injected Error Messages (3)
Teams Direct Routing SBC registration failed — unable to reach Azure Teams backend in East US 2 region, SIP trunk to Teams returning 480 Temporarily Unavailable, all PSTN call routing through Teams offline, 500 users without phone service
Azure Teams Phone System degraded — azure region East US 2 reporting service degradation, Teams calling API returning intermittent failures, azure health dashboard showing incident for Teams/Skype for Business services, PSTN gateway connectivity lost
Teams Admin Center showing calling service outage — azure service health alert for Teams Phone System, all calling policies showing as unavailable, auto-attendant and call queues offline, azure East US 2 telephony infrastructure degraded
Neural Engine Root Cause Analysis
The Teams Direct Routing SBC at 10.10.100.30 is unable to establish connectivity with Microsoft Azure Teams backend services in the East US 2 region, resulting in SIP registration failure and 480 Temporarily Unavailable responses. This appears to be either a regional Azure service degradation, network connectivity issue to Azure endpoints, or SBC service failure preventing proper SIP trunk establishment. The presence of 14 correlated incidents in the same timeframe strongly suggests a shared infrastructure or regional service impact rather than an isolated SBC hardware failure.
Remediation Plan
1. Verify Azure Teams service health status for East US 2 region via Azure Service Health dashboard 2. Test network connectivity from SBC to Azure Teams SIP endpoints (sip.pstnhub.microsoft.com, sip2.pstnhub.microsoft.com) using telnet/ping 3. Check SBC service status and restart SBC services if healthy 4. Verify DNS resolution for Teams endpoints 5. Review SBC logs for specific error codes and authentication issues 6. If Azure service degradation confirmed, engage Microsoft support and consider failover to secondary region if configured 7. Monitor call routing restoration and validate PSTN connectivity for affected 500 users
Tested: 2026-03-30Monitors: 3 | Incidents: 3Test ID: cmncjsbu0048uobqehr2qho85