How to restart the VPN in a sys-vpn?

I installed sys-vpn as a VPN gateway using iptables and CLI scripts as described here:

If the internet drops, the VPN does not automatically re-connect.

How do I restart the VPN connection when it’s dead?

Currently the only way to restart the VPN is to shutdown the connect Qubes, and restart sys-vpn. It’s time consuming.

I tried to run these in the sys-vpn terminal, and failed to restart the VPN connection.
$ sudo service openvpn restart
$ sudo openvpn --config openvpn-client.ovpn --daemon