How to resolve scheduled posts that say "Missed Schedule"

Question

My future posts are getting "missed". They are not getting published on the time they should, and it says "Missed Schedule".

I read somewhere that it could be a server issue, so how can I fix it?

Answer 1

Added the following to my theme's functions.php:

define('WPMS_DELAY', 5);  // Run the below cron task every X minutes
define('WPMS_OPTION', 'wp_missed_schedule');

function wpms_replacements_deactivate() {
    delete_option(WPMS_OPTION);
}
register_deactivation_hook(__FILE__, 'wpms_replacements_deactivate');

// Run the following code on every request
function wpms_init() {
    remove_action('publish_future_post', 'check_and_publish_future_post');
    $last = get_option(WPMS_OPTION, false);

    // Exit here if less than WPMS_DELAY minutes has passed since we last ran
    if (($last !== false) && ($last > (time() - (WPMS_DELAY * 60))))
        return;

    // Find all posts whose scheduled time has passed and publish them
    update_option(WPMS_OPTION, time());
    global $wpdb;
    $scheduledIDs = $wpdb->get_col("
        SELECT `ID` FROM `{$wpdb->posts}`
        WHERE (
          ((`post_date` > 0) && (`post_date` <= CURRENT_TIMESTAMP()))
          OR ((`post_date_gmt` > 0) && (`post_date_gmt` <= UTC_TIMESTAMP()))
        )
        AND `post_status` = 'future'
        LIMIT 0, 10
    ");
    if (!count($scheduledIDs)) 
      return;
    foreach ($scheduledIDs as $scheduledID) {
        if (!$scheduledID) continue;
        wp_publish_post($scheduledID);
    }
}    
add_action('init', 'wpms_init', 0)