Losing audio with Voipfone trunk

[NickG]

Strange issue!

Own office install, all up to date, port forwarding done, been working for years. Win 10 host, local install, Draytek router. All has been fine for years. Recently been losing audio (both ways) on incoming calls only, out going are fine. Temporary solution is to disable the trunk and re-enable it then works fine for a day, several days, only 30 mins or an hour or so. Totally random.

Changed hardware that 3cx runs on, changed router, no change. Have 3CX at home on similar hardware, same model of Draytek router also with Voipfone trunk. No Issues. Have a couple of customers with 3CX both on Voipfone trunks also no issues.

We use IVR for all calls so customer hears nothing, it goes to voicemail when IVR menu is not answered so the call is being answered, this is backed up by the logs. There's just no audio.

Any ideas?

 

[YiannisH_3CX]

Hi @NickG

The first step would be to run the firewall checker to make sure everything is correctly forwarded. To me it looks like a network / Firewall issue since it only happens on incoming calls. It looks like the firewall does not open the audio ports while on outbound calls where the connection is initiated from inside everything works.
Also speak with your provider and ask them to run a trace when the issue starts. They should be able to tell you if audio is being sent back and forth.
You could also try with a supported provider from our list and see if that works. https://www.3cx.com/partners/sip-trunks/
Finally if nothing works you will need wireshark to run traces and locate the issue. If you are not versed in the art of packet captures then speak to one of our partners and get assistance for your issue
https://www.3cx.com/ordering/find-reseller/