Vpn client on Ubuntu

Install the following packages

sudo apt install openvpn network-manager-openvpn network-manager-openvpn-gnome
or
sudo apt install network-manager-l2tp network-manager-l2tp-gnome

Then, restart network-manager

sudo service network-manager restart

For OpenVPN, import the following configuration

sudo nmcli connection import type openvpn file huawei.ovpn

For l2tp, configure IPSec pre-shared key, phase 1 and phase 2 algorithms

Phase1 Algorithms: enc-integ-group 
                   aes128-sha1-modp1024
Phase2 Algorithms: enc-integ
                   aes128-sha1

If it doesn’t work, reboot the computer and try again with the previous command.