Direct Routing to Teams Voicemail not working

Occasional Contributor

Hi Guys,


We have recently discovered that PSTN callers to our Teams clients are unable to hear our Teams VM greeting nor leave VM messages. The VM works fine for Teams - Teams calls and we get the messages in our inbox just fine with that type of call but any PSTN call to the same Teams client just gets dead air when redirected to voicemail. There are no audio issues with these PSTN calls when the calls are answered so this is not a one way audio issue with the SIP etc.


This used to work just fine and I am not aware of any changes nor when it stopped working, any suggestions as to why this could be now happening?




7 Replies



Would recommend @Linus Cansby on this one. He has a ton of direct routing experience. 


@Linus Cansby any reason why PSTN calls to Voicemail would suddenly stop working in a direct routing scenario? Anything in your experience you can think of?


Best, Chris

Thanks Christopher,

We actually have a customer who is experiencing the exact same problem as us.


Since it something that used to work and stopped working I would suggest contacting the partner that setup your direct routing and ask them to see if there are any issues in the SBC setup. Or if you use direct routing direct from your carrier talk to them.

Most common I would say is that you don't hear the first word(s) in the greeting, that that the complete message is quiet.

Thanks @Linus Cansby ,


I actually control the SBC that is linking my PBX to the Teams via Direct Routing. I will go to the vendor and see if they can spot anything. The VM message plays fine for Teams to Teams calls so I know that side of things works but it is just the Direct Routing calls that are failing.



best response confirmed by GerryArmstrong (Occasional Contributor)
I found it, the SBC was trying to do a SDP renegotiate of the codec when Teams transferred the call to voicemail and Teams was not happy with that so the codecs where not the same between the endpoint and the VM system hence no audio. I disabled this requirement to renegotiate and the audio is available on both ends of the call now.

Thanks for your responses guys!
Hi Gerry,

I'm having the exact some issue. I also manage the SBC for my org. Which setting did you change to stop the SDP renegotiation? I can see errors on the INVITE when the call should direct to VM.



Not sure what to answer as the SBC is going to have it named different I bet but it will be something like "SDP renegotiate on transfer" or similar.