Auto Attendant & Call Queue Call forwarding to external numbers failing.

Your tests isolate this to the Auto Attendant/Call Queue voice-application path: internal destinations and user-level external forwarding work, while AA/CQ external transfers fail from 26 July. The changed Azure media-region values are evidence, but they do not alone prove a routing fault or AI-related change.

First, check Microsoft 365 admin center > Health > Service health for a Teams Phone incident and issue history. Run the Teams Auto Attendant diagnostic for each resource account. Confirm each account still has its Teams Phone Resource Account license, service number, and usage location. Reproduce failed AA and CQ calls, then export their PSTN usage records and note UTC time and Call ID. If you use Direct Routing, include the SIP call flow from that report. If service health is clear and diagnostics pass, report the issue or open a Microsoft support case with those records and the first observed failure time.