Ovpn server file must have this line:
log-append /var/log/openvpn/openvpn.log
Make sure to comment:
;log /var/log/openvpn/openvpn.log
You have to enable cron to execute this script:
45 23 * * * /root/monitorvpn.sh
(every day at 23:45 it will execute)
Then, you need to install Apache2 to show the HTML code.
Be sure to remove the default 'index.html' file.