wp-cront doesn't execute for custom events

Hi,
I have scheduled some custom event in my website and for some reason the events don’t execute. The code I have used is the following:

function ztest_add_pages(){
	// Add settings page for users who can edit plugins
	add_dashboard_page('ztest','ztest','publish_pages', "ztest_settings",'ztest_daily_schedule');

}
add_action('admin_menu', 'ztest_add_pages');

  function ztest_installation() {

	/* do some db initialisation stuff */	

	if ( !wp_next_scheduled( 'ztest_daily_schedule' ) ) {
		wp_schedule_event(time(), 'daily', 'ztest_daily_schedule');
	}
}
// Create tables on plugin activation
register_activation_hook( __FILE__, 'ztest_installation' );

function ztest_uninstall() {
	wp_clear_scheduled_hook('ztest_daily_schedule');
}
register_deactivation_hook(__FILE__, 'ztest_uninstall');

function ztest_daily_schedule()
{
	/*doo some stuff, e.g. db queries etc*/
}

I have installed also the wp crontrol (https://wordpress.org/plugins/wp-crontrol/) plugin and I can see that the event is registered properly. However whenever I use the http://mywordpres.com/wp-cron.php?doing_wp_cron or I just press the run button from the wp crontrol plugin for my specific event nothing happens. However whenever I schedule a new post to be published in the future then everything runs properly. I know for sure also that my code runs as I have checked it through the custom page I have created.

Furthermore, looking at the internet there were some other issues such as caching mechanism, hosting companies etc, but none of this is a problem for me. I have even tried it in totally new installed wordpress and for any custom wp cron event I create it doesn’t run.

Any help, ideas?