OpenVPN server Failing to start

Currently I installed openVPN on my ubuntu 14 VPS. When I try to start it from the admin web panel I get this error:

process started and then immediately exited: ['Thu Nov 3 11:17:49 2016 ERROR: Cannot open TUN/TAP dev /dev/net/tun: No such file or directory (errno=2)'] service failed to start or returned error status

When I try to start it from the console:

root@inforcer25:~# service openvpn start openvpn: unrecognized service

EDIT: Here's the tutorial I followed its also my VPS host https://www.pulseservers.com/billing/knowledgebase.php?action=displayarticle&id=3