Why do OpenVPN clients have no audio on incoming FreePBX calls?

Question

Asterisk

The bottom line is this: the OpenVPN remote connects to the OpenVPN office server, passing through the Mikrotik router. From there, using routes, the employee gets from the OpenVPN subnet 10.8.0.0/24 to the office subnet 192.168.24.0/23 and gets access to all its resources, including telephony on FreePBX. From the side of automatic telephone exchanges and telephones, there is a connection to remote workers. Calls from a remote operator to phones within the office subnet work properly, but if you call a remote operator from the office, you can't hear anything.
Which way to look and what to do?

Answer 1

The solution is to click in FreePBX, in the Settings>Asterisk SIP Settings web interface. In the NAT menu, we specify the subnet of the OpenVPN client and everything starts working.

Answer 2

NAT - 90%.
Routing to a remote operator - 10%.

Answer 3

A remoter's network must be added to localnet in asterisk,
plus the remoter must register to the internal address of asterisk
and the stun server must be turned off on the remoter's client in the softphone settings