Solved (Resolved) No Outbound Audio with 15.5.8801.3

[Eric Long]

I just installed 3CX and am having an issue with the 3CXPhone for Windows client, version 15.5.8801.3. When used from a remote location, the client connects properly, shows on-hook, displays presence information etc, and can receive and initiate calls. However, there is no outbound audio from the client during calls. Inbound audio works fine (unless the other end is also a remote 3CXPhone for Windows client - they don't send audio either).

Interestingly, if the remote location is connected via a VPN tunnel to the physical location hosting the PBX, audio works just fine in both directions. Note that even if traveling over the VPN the client is NOT on the same network as the PBX.

AND, just to make things interesting the Free 3CX Softphone, ver 6.0.26523.0, works just fine with or without the VPN tunnel to the office from the same remote workstation.

Any thoughts on what may be happening here?

Thanks.

 

[Eric Long]

A bit of additional information from testing. While the free client works without issue regardless, if I turn off use of the 3CX tunnel in the 3CXPhone for Windows client and set the extension in the System Manager to uncheck Disallow use of Extension outside of LAN then outbound audio from the client works.

 

[YiannisH_3CX]

Hello @Eric Long

From your description it sounds like that the issue is with audio coming through the tunnel. Have you run the firewall checker of the PBX? Do all tests pass? What version PBX are you running?
What happens if you register a client on a mobile device using the tunnel and connect on a 3g/4g network? Do you have audio then?

 

[Eric Long]

Thanks for the hint. It appears to have been a firewall issue - TCP port 5090 was allowed into the PBX, but UDP port 5090 was not. Once reconfigured to allow UDP traffic on port 5090, outbound audio from the 3CXPhone for Windows client began working. I presume that the free 3CXPhone must use TCP for all tunnel connections since it worked without allowing UDP through.

 

[YiannisH_3CX]

Glad to see the issue has been resolved. The old client probably didn't connect through the tunnel but established a direct connection to the PBX that's why audio worked.