02-26-2020 01:49 PM
02-26-2020 01:49 PM
Incoming calls to Microsoft teams get disconnected automatically after 20 seconds. You can make a call from outside, teams phone rings, answer the call, 2 way communication is there but still teams client showing calling on the screen. After 17-20 seconds into the call, it gets disconnect. Sys logs on the SBC shows that Teams is sending BYE signal with
REASON: Q.850 cause 18 text all Controller timed out while waiting for acknowledgement.
Outgoing calls from the same team's client works fine without any issues. Anyone experiencing the same issues? or have a solution? Teams support is working on this issue for 3 weeks now and we do not have a solution yet.
02-28-2020 02:26 AM
We are seeing the exactly same issue with one customer, an another deployment works just fine. Let us know if you hear anything about the solution.
03-03-2020 11:10 AM
@Eerik Kiskonen So far no update, all I am hearing is we are still looking into it.
03-03-2020 04:26 PM
Which SBC are you using? I assume because an SBC is involved, you're using Direct Routing?
03-03-2020 07:25 PM
@jangliss We are using AudioCodes SBC, yes direct routing is involved. Outbound call from teams to PSTN works perfectly but inbound from PSTN is teams disconnects after 17-20 seconds.
03-05-2020 05:18 PM - edited 03-05-2020 05:18 PM
03-05-2020 05:45 PM
03-10-2020 01:40 PM
@Eerik Kiskonen Our issue is finally fixed.
The solution was SBC was sending the IP address in ACK messages for 200 OK it received from Teams. Teams expect contact header FQDN from the 200 OK in the ACK message, not the IP.
03-16-2020 05:44 AM
Great, have to try if that works. How did you exactly change it in the SBC?
04-18-2020 06:24 PM
@Devaraj NarayanappaCould you share with us what is the correct way to send the Contact header in inbound calls?
I am trying like this but occur the same error.
04-19-2020 01:47 AM
Actually for us this was not the reason, the reason was related to the network architecture and the Always Use Source Address parameter. This particular SBC is in a bit strange network configuration where the Teams-facing interface is on the public network and the internal SIP trunk and the user endpoints can only be reached via an MPLS connection of a 3rd party ISP connected to another interface.
The fix was to disable the Always Use Source Address on the SIP trunk IP Group as the SIP trunk could not be reached by Teams.