Input data:
192.168.0.1/24
192.168.0.0
Ovpn server: 192.168.0.1:1194
Protocol: TCP
Using these settings, OVPN works:
Note: works only with Blowfish encryption, without compression.
Additional options in Grandstream phone settings,
don't forget about the route:
client;
dev tun;
resolv-retry infinite;
nobind;
tls-client;
auth SHA1;
route 192.168.0.0 255.255.255.0
Source: habr.com
