Users may be unable to make outbound Public Switched Telephone Network (PSTN) calls in the new Microsoft Teams client

Title: Users may be unable to make outbound Public Switched Telephone Network (PSTN) calls in the new Microsoft Teams client
User impact: Users may be unable to make outbound PSTN calls in the new Microsoft Teams client.
More info: Impact was specific to users who were making outbound PSTN calls in the People App and Live Person card on the new Microsoft Teams desktop client. To avoid this issue while impact was occurring, we recommend that users make calls with the dial pad or switch back to the classic Microsoft Teams desktop client to make outbound PSTN calls as expected.
Additionally, when a user called out from the People App or Live Person card, the callee may have received two notifications of the inbound call. Clicking on the first inbound call notification automatically declined the call, which prevented the call from connecting. However, if the callee clicked on the second notification then the call was successful.
Final status: We’ve monitored telemetry and confirmed that the issue is resolved.
Scope of impact: The problem may have impacted some users who were making outbound PSTN calls in the People App and Live Person card on the new Microsoft Teams desktop client.
Start time: Friday, October 27, 2023, at 7:42 AM UTC
End time: Thursday, February 8, 2024, at 8:00 PM UTC
Root cause: A recent feature update introduced an API code compatibility issue between the classic Microsoft Teams desktop client and the new Microsoft Teams desktop client, which was preventing PSTN call functionality from working as expected when making calls from the People App or Live Person card.
Next steps:
– We’ve identified and are implementing additional code updates to further strengthen the service and help ensure similar issues don’t occur in the future.
This is the final update for the event.