In many situations, the WP-Cron may not working well or work at all. By default WordPress is setup to call wp-cron.php only when someone visits your site.
A better way to use the cron job that is available on your hosting server. In your cpanel, look for your cron job icon, click on it and select Add New Cron Job, then add the following line.
Using wget or curl since some host may have curl install instead of wget
wget -q -O - http://myurl.com/wp-cron.php?doing_wp_cron >/dev/null 2>&1
or php cli
If you have access to ssh, simply type
This will open a file for you where you will be able to add the line above.