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rudimentaire's avatar
rudimentaire
Copper Contributor
Apr 23, 2026

Direct Routing PSTN calls to Teams Auto Attendant does not forward to Shared Voicemail

Hi all, I’m running into a strange issue with a Teams Auto Attendant and I’m hoping someone here has seen it before. We have a Direct Routing number where business hours calls go to a Call Queue, w...
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Ahmed_Masoud97's avatar
Ahmed_Masoud97
Steel Contributor
Sep 10, 2026

Your diagnosis is right, and the external transfer failing the same way is the giveaway. Shared voicemail and external redirect both re-originate the call outbound. Internal redirects don't. That outbound leg is what's broken.

Check media bypass on the PSTN gateway first. The redirect renegotiates media and the SBC and Teams media processors often can't agree a path. Disable it temporarily and retest.

Then check the outbound route from the resource account. A voice routing policy being assigned isn't enough, it needs a PSTN usage and route that actually matches, and the SBC has to accept the resource account's number as calling party. Plenty of SBCs only accept calling numbers in a defined range, and resource account numbers sit outside it.

Get an SBC trace on a failing call. 488 means media negotiation, so it's bypass. 403 means the SBC or carrier is rejecting it, so it's routing.