I can't get MicroSIP to work with FreePBX. In which direction to dig?

Question

SIP

Good afternoon!
Client connection to FreePBX is organized according to the scheme: FreePBX - Gateway-1(NAT) - Internet - Gateway-2(NAT) - MicroSIP.
UDP ports 5060, 7140, 11000-20000 have been forwarded on gateway-1. An account is set up on MicroSIP, connection to FreePBX is going on (checked by the OnLine indicator on MicroSIP). But it is not possible to make a call to an internal subscriber, timeout.
If the connection scheme is changed to FreePBX - MicroSIP, then everything works.
Requests from MicroSIP through NAT to port 5060 FreePBX pass, checked through the logs.
There is a suspicion that the gateway-1 is not configured correctly, but I can not understand where exactly. In which direction to dig?

Answer 1

Solution found. It turned out that in the MicroSIP account settings it is necessary to fill in the SIP proxy field with the same value as the SIP server field (ip-address and connection port) and everything started to spin.