No audio when traffic routes call to IVR

[PeterCheng]

Hello sir,

3CX version: 18.0.3.461
We have a on-premise 3CX server in our office and everything's fine.
Recently we add a new ISP SIP trunk with internet IP and we can call out successfully, and audio seems normal.
While we test the inbound call through this line, and try to route the call to our IVR, we found that no audio there.
I tried to use phone extension instead of the IVR, the phone will ring. But when picking up the call, it's still no audio.
And the call was still established.

I wonder whyI cannot hear any cound when call was established, but if I call out, everything's fine.

 

[YiannisH_3CX]

Hello @PeterCheng

This could be a number of things so you need to start from the basics. Can you pass the firewall checker? Is your port forwarding set up correctly?