If you are caching (parts of) your site, manually or via a plugin (such as WP Super Cache, for instance), it might have a negative impact on the functionality of wp_cron.
If done via a plugin, disabling it might not suffice, as WP Super Cache for example does not clear the page cache it has created upon deactivation.
If you want to keep caching active, a solution might be to setup a manual Cron Job for the php file /wp-cron.php