Call queue not working when second person try to call to queue number

Copper Contributor

Hi Everyone,


We have configured direct routing to teams from our sbc audiocodes with sip trunk. I was create a call queue in Teams admin center with an assigned on prem number. The resource account has a Teams Meeting Room Standard license. When the first person calls, the queue comes forward and redirects to the appropriate person. Unfortunately, when at the same time another person calls to the queue number, instead of connecting to the queue, hears only a beep beep beep and is disconnected. Maximum calls in the queue is 50. I tried different Routing method settings but always the same effect, beep beep beep ... I think it is somewhere in the sbc audiocodes settings. Have any of you encountered such a problem?




6 Replies

Hi @antoonioo84, first of all I would suggest to setup the call queue in a supported way by Microsoft. Therefor you must request "Teams Phone System - Virtual User" licenses for your resource accounts. Ask your CSP, license vendor or request the licenses directly in the Microsoft 365 Admin Center -> Billing -> Licenses. The licenses a free of charge and at no costs for you.

Normally the SBC will route the incoming call to Microsoft Teams and the call queue service. So, I would first check the Call Queue settings. What are the settings for Call overflow handling? How many calls can be handled in the queue? What is the action to the callee when the queue is full? What is the wait time and what is the action for the last callee?

Do you have the option to create a syslog from the Audiocodes SBC and to post the SIP Call flow if necessary?

@Thorsten Pickhan I assigned Teams Meeting Room Standard license because they contain Phone system option. I bought the Teams Phone System - Virtual User licenses for the admin center and assigned them to the resource accounts, but so far no effect after 24h. The connection queue settings below are correct in my opinion.


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Merry Christmas!

Hi @antoonioo84, thanks for sharing the information. Great that you modified licensing for the resource account. The settings for the call queue are looking fine and correctly. Just to clarify: first inbound call is working as expected and a second call is terminated with beep-beep signalling?

So, you configured an attendant routing method and 50 waiting slots in you queue. In the next step we should analyse the Audiocodes settings. Can you provide a screenshot of the SIP message flow for an inbound call to the call queue? To get a SIP flow diagram you need to analyse the syslog messages during the inbound call. Please pay attention to modify the SIP flow diagram and to grey out confidential data like IP address of the SBC, called number and calling number.


Out of the curiosity? What is the Calling Policy set on the resource account? And what is the calling policy for agents in queue? Is it with Busy on Busy enabled? If so I would try to change the Calling policy to the policy which is not having busy on busy enabled.
I do not believe that this should have any effect on call queues' resource account but eventually it might be the reason for busy tone on second call when there is only one agent and this one is already busy with first call. 

Just guessing... but as Thorsten suggested I would recommend to have a look on reason codes for closure of the call on side of Teams, on side of SBC, this should provide more clarity about the call which is failing. 




please Note:

the Calling Policy only affect outgoing or transfer PSTN Calls to outside.

This don‘t have affect for incoming calls. 
An incoming TEAMS CallGroup Call will only be an offer for available Agents - not a direct Call. 


Calling Policy also contains parameters for "Busy on Busy".

This does affect behavior for multiple inbound calls to user assigned with that policy.