Missing Refer from MS Teams for AA calls

New Contributor

Hi everyone,


I have a MS Teams Carrier setup and occasionally PSTN to AA then to MS Teams user transfer will fail. Investigation on SBC logs seems to indicate no REFER from MS Teams. MS Support believe they have sent the REFER.

Has anyone seen this issue before? 

4 Replies
I know you say the SBC doesn't receive a REFER but just in case, it's missed your checks. Are you also aware that there is some SBC configuration to be done around REFER.
For Ribbon, refer here:

Audiocodes would have their own required configuration or any other vendor.

Hi Fowler_23,

Yes I well aware of the SBC config for REFER. However we can see from SIP Signalling trace that the SBC didn't receive REFER on the wire. Unfortunately we are not able to do third party packet trace on switch or router as all the signalling are encrypted.
I have same issue that Refer is not seen in SBC logs from Microsoft end, can you tell me how you solved this issue





Did you ever find the root cause for this issue? Experiencing this on two different tenants.