Teams Direct routing - no BYE message from Teams

Occasional Contributor


We have a following problem with Direct Routing SBC: call is established between mobile phone and Teams via SBC. Teams side ends the call, but this signaling (SIP BYE) never reaches mobile phone. On mobile phone call remains ongoing, and will remain until mobile phone hangs up.

In our solution SBC is implemented as VM at Microsoft Azure. Analysis so far showed that such BYE message never reaches SBC. Problem is sporadic, but can be provoked rather easily: 1 out of 10-15 test calls results with such behavior. 

Please, had anyone faced the same problem with Direct routing? Any hints for the solution?  

Problem tickets were opened against Microsoft Teams and against Microsoft Azure, but no results yet. 

Best regards, 



8 Replies
I can't say I've seen that. Does it only happen with calls to mobile phones? Is it to a specific number, or all calls? Out of curiosity, what SBC? Do you have a copy of the sip trace?
Same here for 100% of the calls. Scenario is when calling from external to Teams client. When the Teams side disconnects the BYE message never reached our on-prem Avaya SBC. We don't use Media Bypass. Setup is straight forward with only 1 SBC , 1 route pattern and 1 policy.

This must be something within the Teams environment. Any one any thoughts?

Thanks in advance.
We are using Metaswitch SBC (now also Microsoft company), but the problem should not be at SBC. Based on our experience, testing with real Metasw. SBC is not showing this behavior. Problem is present only if SBC is deployed as VM, so this looks like Azure problem.
The issue is not related to any specific number.
SIP trace taken at SBC looks like normal SIP call, except BYE sent from mobile is rejected from MS Teams with 481 Call Leg/Transaction Does Not Exist. This is I believe also correct, because from Teams point of view, call was already released at that point.
Hi Jacco,
I have same your scenario. Any news on your issue? Have you then solved it?
Thanks in advance
Hi Allessandro, this was resolved after updating the Avaya IPO to the latest release. In this release the line is not configured as SIP line but as MS Teams Line. Regards Jacco.
BTW, the SBC was on release 8.1.3 in this scenario.
Hi Jacco. My scenario is with Aura instead IPO. Anyway, thanks a lots for your reply.. I hope to have other chance with a SR on Avaya. Best regards! Alessandro
@Alessandro_Gloria did you manage to fix this. We are also experiencing the same problem where the BYE does not appear to be received by the Avaya SBC. Teams ends the call but it stays open through the mobile phone.