3CX Windows client 16.3.0.144 Audio stopped working

[[email protected]]

After upgrading our Windows clients to 16.3.0.144, we are exipirencing problems with audio. When establishing calls, receiving audio is not working, whilst outgoing (send from microphone) is OK. This is the case only for Windows clients, for IOS and android are working fine.

 

[[email protected]]

A small update to the problem, looks like this is the case only with calls between Windows apps. There is no issue with traffic between Windows app and mobile apps, or windows app and IP Phones.

 

[JohnS_3CX]

Hi Vladimir,

- What version is your PBX?

- Is this a cloud PBX or Local PBX?

- Where are the clients in relation to the PBX?

- Are you using a VPN for the PCs to connect to the internet?

 

[[email protected]]

Hi,

Here are the answers:

We are running v. 16.0.5.612,

It is a Local PBX, installed on a VMWare virtual machine,

Clients are accessing PBX through internet, using public IP with mapped ports.

We are not using VPN for internet access, however, all PC's are pretty much constantly connected to remote site where, among other servers, is PBX.

General conclusion is that problems started with the latest update on the windows clients, and are affecting only windows client to windows client traffic. Traffic to other clients and outside phone numbers are working fine.

 

[JohnS_3CX]

Thanks,

1. can you also explain a bit more when you say "We are not using VPN for internet access, however, all PC's are pretty much constantly connected to remote site where, among other servers, is PBX."

2. Can you confirm the 3CX firewall checker passes?

3. Can you confirm if the extensions in question are configured like this example?

 

[[email protected]]

Hello,

Thanks for your reply.

About VPN, what I meant is that we are using VPN to access our servers in IBM Cloud, but it is split tunnel, with internet traffic is not routed through VPN tunnel.

All settings you attached in the screenshot are as you suggested.

The problem started after upgrade to the latest windows app.

 

[JohnS_3CX]

You may have to inspect the client traffic in this case and see where it is actually routed.

Specifically the client will try to connect to these two destinations:



Whichever one replies first will likely be the one you connect to.
The In Office setting for the app is governed by this option here


So a) depending on what option you have set there and b) how the network routing works on your PC that uses the client, you may inadvertently be in a scenario that affect the client's ability to connect properly.

 

[[email protected]]

Thank you for the detailed clarification. I have gone through the settings, and everything seems to be in order. What's interesting is when I downgrade Client application, everything works OK. Problem arises only with the latest app.

 

[[email protected]]

Hello JohnS_3CX,

I have tried the beta application that you sent, but with the same results. I followed your instructions, tried a call with the latest version installed, which behaved as expected with audio problems. After that we tried the version that you sent, and we got same problem. After this, we downgraded to older version (16.0.1.81), and it was working fine.

 

[JohnS_3CX]

Would you like to create a test extension and send me the config file?
(upload in dropbox or other public drive and send me the link)

I'm curious if I will also have the same problem from here

 

[Luca Gatti]

Hello JohnS_3CX

We have got the same problem. Our PBX version is 16.0.3.676

After upgrading client version to 16.0.3.144 we have audio problems: sometimes it works and sometimes not. When audio stops working from Windows client, the only way to have it back is to reboot the PC.

I've double checked all the configurations and are ok. Took wireshark capture too, where I simply cannot see any RTP traffic: the client does not send it

Have you got any update on this issue ?

Thanks

Luca

 

[JohnS_3CX]

Hi Luca,

Your issue appears to be different,Vladimir always has no incoming audio but has outgoing audio working fine.

You can disable the tunnel on the client from the extension settings, and then reprovision it. Then retry to capture from the PBX and the PC (you must compare both captures). But better start a new thread in this case so we do not cross 2 separate cases in one thread.

 

[Luca Gatti]

Hi JohnS_3CX

Actually I said it badly. We have the same behaviour of Vladimir. When I make a call (or answer to it) I can hear the audio but the intelocutor no. In this situation, taking trace with Wireshark, I cannot see any RTP traffic outgoing.

As Vladimir says, it seems that the problem affects only calls beetween 3CX clients

Thanks

Luca

 

[JohnS_3CX]

Hi Luca,

Vladimir said receiving audio is not working (so they cannot hear the interlocutor whereas you can).

In your case, I would suggest to quickly check this Windows option, just in case the mic is being blocked.


Then, you can disable the tunnel on the client (to makes traffic visible) and run a capture again from the PC and from the the PBX Activity Log section. Compare them both:

- Does the PC send and receive audio to the PBX ip?

- Does the PBX capture also agree with the PC capture?