Microsoft 365 Alert – Service Degradation – Microsoft Teams – Users may be unable to answer PSTN calls from call queues using any Microsoft Teams client – RESOLVED

19/12/2025 14:50:00 PM

NHSmail Reference: INC46709630

Microsoft Reference: TM1199346

Issue Status: Resolved

Issue Description: Users may be unable to answer PSTN calls from call queues using any Microsoft Teams client.

More info: When answering PSTN calls from call queues, affected users experienced calls that remained stuck in a loading state, preventing connection establishment.

While Microsoft worked on a fix, non-Virtual Desktop Infrastructure (VDI) users could disable the setting (Settings, Devices, “Sync device buttons”) as a temporary remediation.

For optimised VDI users that didn’t have the option to toggle the “Sync device buttons” setting, some users could work around this impact by accepting PSTN calls using a non-human interface device (HID).

Final Status: 24/12/2025 08:46:00 AM – Microsoft has deployed the fix to the affected environments and verified with affected users that this action successfully remediated the problem.

Scope of impact: Impact was specific to some users attempting to answer PSTN calls from call queues using any Microsoft Teams client.

Root cause: A recent service update that intended to address an unrelated service problem introduced an impacting code regression that was preventing users from answering PSTN calls from call queues using the Microsoft Teams client.

Next steps: Microsoft are investigating how the recent service update intended to address an unrelated issue introduced a code regression that prevented users from answering PSTN calls from call queues using the Microsoft Teams client, to help prevent this problem from occurring again.