Intermittent No Audio received on inbound calls

[JDesjardine]

• 3CX Version 18.0 Update 3 (Built 461)
• Server OS, Windows Server 2022
• Is the 3CX Server Hosted and where? Hosted by 3CX
• IP Phone Make/Model/Firmware version,Yealink T58A version 58.86.0.39
• Provisioning Method: SBC
• Trunk Provider or VoIP Gateway Make/Model Skyetel
• Has the Firewall Checker passed: Not fully,SIP ALG (Failed), Meraki does not utilize SIP ALG
• Are custom Phone Templates being used: No
  Incoming calls will sometimes have no RTP traffic or audio from the caller end, resulting in dead silence. However, if the user calls multiple times, it connects and the call is fine. We have had Meraki double check our network environment to ensure our VOIP traffic is optimized and shaped correctly.

 

[YiannisH_3CX]

Incoming calls will sometimes have no RTP traffic or audio from the caller end, resulting in dead silence.

You mean that no audio packets come to your firewall? Did you run a packet capture on the firewall to verify?
Did you try replicating using a webclient or a 3CX mobile app?

 

[JDesjardine]

You mean that no audio packets come to your firewall? Did you run a packet capture on the firewall to verify?
Did you try replicating using a webclient or a 3CX mobile app?

This is how the audio looks when it hits our call queue there is no one on the other end. When they call back there is a 50-50 that there will now be a person on the other end until they call back again.

 

[YiannisH_3CX]

If there is no audio coming from the provider to the PBX then there are not a lot we can do from our side. Your next step is to look at signaling and see if the ports and IPs are correct.
Also you may need to look into why the firewall checker is not fully passing. ALG test failure might mean that there is something misconfigured there.

 

[KatrineHelena]

Hello, is it when the caller calls directly to the number?
Or is it when the call gets redirected from one call queue to another?
We're experiencing something similar.

Is this case solved?