VPN on virtual machine

[Jim]

I decided to try a virtual machine for bittorrent.  The host machine 
runs kubuntu 14.04 with 4GB RAM. I've installed virtualbox 5.2.18.  The 
virtual machine is running lubuntu 18 and has 1GB RAM.  The problem is 
with the vpn.  I can't get openvpn or pptp to work.  I configured them 
using the same instructions I did on the host machine.  When I try to 
start a VPN connction(openvpn or pptp)  on the guest machine, the icon 
appears to show it's trying to connect, then it just stops without 
offering any error message.  In  Virtualbox's settings for the guest 
machine under network, I chose attached to NAT.

Any ideas what I should do different?

thanks