If you setup Ubuntu 18.04 with openvpn you must install all Network Manager Plugins to run a stable VPN
sudo apt-get install network-manager-openvpn network-manager-openvpn-gnome network-manager-pptp network-manager-pptp-gnome network-manager network-manager-gnome
This fixes dependencies of Plugins to openvpn like pptp and more!
The Syslog does not show any informations whats happening!
only like this:
vpn-connection[ID-XXXX-XXXX-XXXX-XXXX,”vpn”,34:(tun0)]: VPN plugin: failed: connect-failed (1)