agfeo phone system behind pfSense

[OkTech]

Good day,

Today we changed the telephony from Telekom (ran on a Fritzbox) to GVG fiber. Now I want to run the phone system with the fiber network behind my pfSense. Calls go out, but callers can't hear each other and incoming calls unfortunately don't work at all.

I have used the following NAT rules:

I also have the following rule in the firewall under WAN:

and under the network of the PBX the following rule:

Finally, here are my aliases to ports and IPs:

Do you have any idea how I can solve this problem or where the error is in my configuration?