Final Microsoft Status
We've routed the affected call requests to a healthy portion of service infrastructure and confirmed through monitoring service telemetry that impact has been remediated.

User Impact 

Any user attempting to make calls routed through Auto attendants and Call queues within Microsoft Teams may be impacted. 

Root Cause 

Auto attendant and Call queue call routed call requests are being routed to an unhealthy portion of service infrastructure, resulting in impact.