After upload the .tar file I got this screen :

When try to activate the OpenVpn on Akuvox :

The structure of the tar file is :

vpn.conf :
client
dev tun
proto udp
remote My_Public_IP Openvpn_Port
resolv-retry infinite
nobind
ca /config/openvpn/ca.crt
cert /config/openvpn/akuvox_810_020518.crt
key /config/openvpn/akuvox_810_020518.key
On other IP Phone I upload only a client.ovpn file and have no problem. Can you help me ?