3cx internal Call problem (windows 2016 server)

[Tasospan]

Hi I have 3cx on HyperV (win16 server) 35 ip phones(yeahlink and fanvil) all poe connected to Cisco WS-C3560G-48PS-S Catalyst 3560G 48-Port PoE Gigabit Ethernet-Switch.
I have a problem with the internal calls....sometime when an extension call another extension noone hears anything...they pick up the phone but no sound... I have tried the "PBX Delivers audio" solution but it happens even with that....
Do you think its something wrong with the switch??
Any suggestions?

 

[mortenjorge]

Hi Tasospan,

We have a customer with a case that seems to be close to each other.

Could you please press "HOLD" next time it happens and then unhold it again? does the sound works now?

In our Customers case, this resolves the issue.

Thanks.


- I would check for SIP-ALG in your case.

 

[Tasospan]

I'll try it... but if it works what will this mean? is it a network problem? what should I look for?

 

[mortenjorge]

Thanks,

I would start a wireshark trace, and check what is going on.
Is the phones and 3cx on the same subnet?

Could be a network problem, but hard to say before we know what happens.

 

[Tasospan]

yeap the phones and the 3cx are on a separate network...alone...no connection to my pc network....

 

[mortenjorge]

Start a wireshark trace on the 3cx server and start a pcap trace on the yealink phone and try to replicate the issue.

Please try the HOLD function when the issue happend. and stop the trace afterwards.

Then i can check if its the same problem that occurs at our customer.

 

[Tasospan]

ok thanks

 

[Alphabetic]

Is it only the Fanvil's that cant hear the caller by any chance?

 

[Tasospan]

Well Yeap cause all of them are fanvil except one console which is yealink

 

[Alphabetic]

And it only happens on transferred calls?

Are you on the latest firmware by any chance?

 

[Tasospan]

Not only in transferred calls..it is also happening when an extension calls another...and it doesn't happen all the time..And randomly...
I have tried with the latest firmware of the phones and the one that 3cx recommends

 

[Alphabetic]

first check to see you have the latest fanvil templates and then factory reset two phones and set them up with the default templates then test.

Am I right in assuming these phones are set up on LAN??

Have you rebooted the switch?

Is it a managed switch?

Can you try another switch?

It does sound like a network issue here. However I’ve recently had an issue with the hold function on my fanvils and my temp solution is this X4 firmware provided by Nick W. It works for now.

Bear in mind this isn’t supported firmware and is entirely for testing purposes to see if it fixes your problem. I would however go down the network diagnostic route though.

https://1drv.ms/u/s!AuC_LI6SkKdPhLo8DxUuX9EdmjZdPA

 

[Tasospan]

The phones are in lan...it's a Cisco switch as I mentioned above....I don't have another switch..but I'll buy one to test it....thanks for the help