Connecting to a VPN pppt using pptp-linux

I have a pi running raspbmc and it works fine but I would like to change it to OSMC but when I do pon XXX in OSMC although it creates a ppp0 in ifconfig it isn’t listed in the gateway address and doesn’t connect. After a short while it disappears from ifconfig. To get back to normal running I have to poff XXX other wise the processor is running at 100%. Any suggestions would be greatly appreciated.