Microsoft Teams users are experiencing an unexpected issue where autogenerated chat threads appear during Public Switched Telephone Network (PSTN) calls, including those routed through Call Queues and Auto Attendants. The service degradation, first reported on February 25, 2026, is impacting users attempting to make or receive calls through the Teams platform.
According to an internal NHSmail alert (INC46758255) and a corresponding Microsoft reference (TM1238395), the problem manifests as a latest chat thread being automatically created within the Microsoft Teams desktop client and web app whenever a PSTN call is initiated or received. This behavior extends to calls handled by Call Queue and Auto Attendant systems, adding an unintended layer of communication during voice interactions.
Microsoft has acknowledged the issue and has begun deploying a fix in stages. The company stated that the staged rollout is designed to allow for careful monitoring and validation before wider implementation. Users can expect to see remediation incrementally as the deployment progresses, though a specific resolution timeline has not yet been provided. The next update is scheduled for Wednesday, February 25, 2026, at 6:30 PM UTC.
Root Cause and Scope of Impact
The root cause of the problem has been identified as a code issue introduced in a recent deployment to the Microsoft Teams calling service. This issue has created a compatibility complication between the calling scenarios and the chat functionality, leading to the unintended autogeneration of chat threads.
The scope of impact is potentially broad, potentially affecting administrators updating the MacOS Wi-Fi policy for users on build 6.2602.7.2001 forward through Microsoft Intune. While the initial alert focuses on this specific configuration, the underlying code issue could affect a wider range of Teams users.
Understanding PSTN Connectivity with Teams
Microsoft Teams Phone, leveraging Microsoft’s Calling Plans, provides a cloud-based voice solution connecting the Microsoft Phone System to the Public Switched Telephone Network (PSTN). This allows Teams users to make and receive calls to traditional landlines and mobile phones globally, as detailed in NHSmail support documentation. Microsoft’s Tech Community blog highlights the flexibility of Teams Phone in managing different PSTN connectivity types to optimize calling scenarios.
The NHSmail Teams Phone System is a standalone service, separate from the standard Teams Phone System for outbound calls, as noted in the NHSmail support documentation. This distinction is vital for understanding the specific context of this service degradation.
What to Expect Next
Microsoft is prioritizing a swift resolution to this issue, with ongoing monitoring and validation as the fix is deployed. Users experiencing the autogenerated chat threads are advised to remain patient as the rollout progresses. The company will provide a more definitive timeline for complete remediation once available.
As organizations increasingly rely on Teams for unified communications, addressing these types of service disruptions is crucial for maintaining productivity and seamless collaboration. We will continue to monitor the situation and provide updates as they become available.
Have you been affected by this issue? Share your experience in the comments below.
