Hi all,
My organisation is planning a move to direct routing. We have an AudioCodes VE SBC. I've been working on this for awhile and got everything to a pretty decent state.
I've come across an issue which is fairly new as I remember testing this months ago, when I was still trying to figure out how to deal with REFERs coming from MS Teams on call transfers.
So the call flow is as follows:
Incoming call from SBC to MS Teams -> MS Teams user transfers the call to internal user -> Call fails as MS Teams generates a REFER back to the SBC rather than route the call internally to MS Teams user target.
The issue I'm observing aside from MS Teams routing the transfer leg of the call is that the REFER-TO user part of the URI is blank. Please see the attached screenshot.
Its as if MS Teams is treating this as an external transfer and does not know how to populate the user part of the REFER-TO header. I've tested this with both users set up with Phone system and DDIs assigned to the user and users which have no phone system add-on or assigned DDI.
Please note that if you tried to transfer the call to a PSTN number, that works fine. I'm unsure if this would be something config related within our Teams tenancy or a genuine bug. I'm more inclined that this is the former rather than the latter as it does seem like fairly basic functionality and I'm confident this used to work a few months ago.
Any advice would be appreciated.
Kind Regards,
Sim
