Incoming calls in a queue are terminated

[Oleg Sviryd]

We have a hosted 3CX 18 installed on Debian wit the latest updates (server - 18.0 (Build 461), windows app client 18.8.508). It is configured with one sip trunk and 1 Call Queue.
In 90% of incoming calls we are facing with issue of dropping queued call after 20-th seconds with the next logs:

04/18/2022 3:00:16 PM - Leg L:373.2[Queue:800] is terminated: Cause: BYE from local

04/18/2022 3:00:10 PM - Leg L:372.2[Queue:800] is terminated: Cause: BYE from local

04/18/2022 2:59:56 PM - [CM503007]: Call(C:373): Queue:800 has joined, contact <sip:[email protected]:5483/UDP>

04/18/2022 2:59:56 PM - L:373.2[Queue:800] has joined to L:373.1[Line:10001<<+INCOMING_MOBILE_NUMBER]

04/18/2022 2:59:56 PM - [CM505001]: Endpoint Queue:800: Device info: Device Not Identified: User Agent not matched; Capabilities:[reinvite, replaces, able-no-sdp, recvonly] UserAgent: [3CX Queue] PBX contact: [sip:[email protected]:5060]

04/18/2022 2:59:56 PM - [CM503002]: Call(C:373): Alerting Queue:800 by contact <sip:[email protected]:5483/UDP>

04/18/2022 2:59:56 PM - [CM503025]: Call(C:373): Calling T:Queue:800@[Dev:sip:[email protected]:5483;rinstance=3af0b985d820b0af] for L:373.1[Line:10001<<+INCOMING_MOBILE_NUMBER]

04/18/2022 2:59:56 PM - [CM503027]: Call(C:373): From: Line:10001<<+INCOMING_MOBILE_NUMBER ("+INCOMING_MOBILE_NUMBER" <sip:[email protected]:5060>)  to  T:Queue:800@[Dev:sip:[email protected]:5483;rinstance=3af0b985d820b0af]

04/18/2022 2:59:56 PM - [CM503004]: Call(C:373): Route 1: from L:373.1[Line:10001<<+INCOMING_MOBILE_NUMBER] to T:Queue:800@[Dev:sip:[email protected]:5483;rinstance=3af0b985d820b0af]

04/18/2022 2:59:56 PM - [Flow] Call(C:373): has built target endpoint: Queue:800 for call from L:373.1[Line:10001<<+INCOMING_MOBILE_NUMBER]

04/18/2022 2:59:56 PM - [Flow] Target endpoint for 800 is Queue:800

04/18/2022 2:59:55 PM - [CM503007]: Call(C:372): Queue:800 has joined, contact <sip:[email protected]:5483/UDP>

This behavior happens only when the number of active call agents less then nubmer of current calls. For instance, when we have 2 active agents then the third simultaneous call drops

3CX is hosted behind of NAT router mikrotik, SIP alg is disabled.

Could you with this issue?

 

[YiannisH_3CX]

Hi @Oleg Sviryd

If you run the firewall checker does it pass all tests?
When you have only 2 calls and 2 agents do calls work normally?
What is your Queue ring time?
What is your Maximum Queue wait time?
What is your destination if no answer for the Queue?

 

[Oleg Sviryd]

Hello.
1. Yes, I've tested several times, it is ok.
2. Yes, it is working without issues.
3. 300 seconds
4. 1800 seconds
5. End call

 

[YiannisH_3CX]

Thank you for the information. Can you try to replicate the scenario by making a call from an internal extension of the PBX? So when the 2 agents are busy try calling the queue directly and see if the call is also dropped.
Also are there any third party tools installs that might be causing this?
Do the extensions only have the Windows app installed or does the queue ring other devices as well like mobile phones or IP phones?

 

[Oleg Sviryd]

Hello.
Thank you for your fast response.

We did such tests and have some similar results. In case we have 1 internal call between two agents we found that the 1 external mobile call was held on line and properly switched to the first free agent lately. But when we tried to do the same with 2 simultaneous external calls, the second call were dropped at 19-th second.
More detailed log I've attached to this message.

We don't have any tools on premises server. It was install only 3cx application.

As for remote connections from users' perspective they have only 3cx web app on theirs desktops and don't have any sip phones or mobile 3cx apps.

 

[YiannisH_3CX]

Thank you for the additional information. To further troubleshoot the issue we will need a few more things so I will send you a p.m. shortly with further instructions.

 

[Oleg Sviryd]

Thank you for your help.

[Edited by Administrator]