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 10.70.30.10/24.
After installation, I only configured internal telephony. I configured via “Setting”->“Asterisk SIP settings” only local networks (10.70.0.0/16 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
server 10.70.31.0 255.255.255.0
push “route 10.70.0.0 255.255.0.0”
ifconfig-pool-persist ipp.txt
client-config-dir ccd
client-to-client
keepalive 10 120
cipher AES-256-CBC
max-clients 100
persist-key
persist-tun
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 10.70.30.0/24 ring and work fine
  2. Phones 1578 and 1579 (through openvpn and receiving addresses in 10.70.31.0/24) 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?