Call is registered but no audio

[wabru]

Hi
I moved from an ancient RPi with FreePBX v12 to a RPi P3 with FreePBX v15.
Same settings, same phones connected, same VoIP provider.
When I call an external number, the callee’s phone rings, but no audio on both ends…
When I get an external call, my phone rings, but no audio on both ends.

(SIP ALG is deactivated on the router).

Any idee what the problem might be and how to fix it?

Thanks for helping

[cynjut (Dave Burgess)]

One-way audio, even when it’s going both ways, is a NAT problem.

First, make sure all of your NAT settings are correct. Pay special attention to your Advanced SIP settings. Also, double check the addresses you have listed for the “external” and “internal” addresses and make sure they are all in the server correctly.

Second, make sure that you are forwarding UDP port 10000-20000 to the PBX from the Firewall. This should help you with your Inbound Calling.

[wabru]

Thanks.
Meanwhile I reinstalled FPBX and now the audio works.
The only problem: I don’t know why …