OpenVPN way is not ringing

Hi, all!
I installed FreePBX out of the box with the current version 2204-1. The server IP address is
After installation, I only configured internal telephony. I configured via “Setting”->“Asterisk SIP settings” only local networks ( as local). And I create 4 extensions: 1511, 1512 and 1578, 1579.
Next, I set up the distribution’s built-in OpenVPN Server. Its config file is below:

port 1194
proto udp
dev tun
ca /etc/openvpn/easyrsa3/pki/ca.crt
cert /etc/openvpn/easyrsa3/pki/issued/OpenVPN-Server.crt
key /etc/openvpn/easyrsa3/pki/private/OpenVPN-Server.key
dh /etc/openvpn/easyrsa3/pki/dh.pem
push “route”
ifconfig-pool-persist ipp.txt
client-config-dir ccd
keepalive 10 120
cipher AES-256-CBC
max-clients 100
status openvpn-status.log
log /var/log/openvpn.log
log-append /var/log/openvpn.log
verb 3

In addition, a line has been added to the /etc/sysctl.conf file net.ipv4.ip_forward=1.

After that, the following situation occurs:

  1. Phones 1511 and 1512 in the local segment ring and work fine
  2. Phones 1578 and 1579 (through openvpn and receiving addresses in call local and work fine
  3. Local phones 1511 and 1512 when making a call to remote phones (OpenVPN clients) ring, i.e. a dial tone is heard on the handset, but there is no call on your remote phone.
    All phones ping each other.

What could be the problem?