Router setup

Good afternoon.

Offering extra earnings. I installed the Padawan firmware on the router.
Installed Asterisk16 with a USB GSM modem for organizing a GSM gateway.
I have configured two internal SIPs, two external SIP Zadarma and one USB modem GSM dongle E173.
Two internal numbers are calling each other on Zoiper.
GSM is calling internal numbers.
The internal numbers are calling Zadarma.
GSM doesn’t call Zadarma – the call goes, connects, the connection ticks, but the interlocutors do not hear each other.

For two days, I struggled with Asterisk, NAT, port forwarding, and so on. No result.

I need help setting up.