Teams call transfer failed - Audiocodes VE

Copper Contributor

Dear Colleagues,


I have setup an Audiocodes VE Direct Routing SBC, but during the tests I noted that I was not able to forward calls. As I can see, during the REFER process there is a 488 Not Acceptable answer, because of media mismatch between the Mediant and the O365. The p2p calls are working properly in every direction.

Have you experienced this kind of problem?


I have attached the SIP log (in .xlsx format, since .txt is not allowed), and the participants are:

10055 – Teams (Transferor)

20055 – CUCM registered phone (Transferee)

80000 – Mediant registered phone (Transfer target)




5 Replies
I was able to resolve this by setting up the Refer to be handled locally

@Henry Morales In which option of the configuration did you make the adjustment?

@Cristian Arguello this was setup on the AC SBC > SIP Trunk IP Profile > SBC Forward and Transfer.

Remote REFER Mode = Handle Locally

Remote Replaces Mode = Handle Locally

Remote 3xx Mode = Handle Locally




Hi @Henry Morales, Audiocodes suggests creating a special SBC Routing rule in the IP-2-IP section, too.

Check the official manual on page 40

Connecting AudioCodes' SBC to Microsoft Teams Direct Routing Enterprise Model Configuration Note


SIP REFER Audiocodes IP-2-IP Routing.jpg


@Henry Morales  Thanks. that was a quick fix.