Fix WordPress missed scheduled posts

You plan ahead, write your posts in advance, schedule them for publication — and a few days later you notice nothing was published. WordPress shows a “Missed schedule” error and your scheduled posts are still sitting as drafts.

This happened to me for several weeks. I searched online and asked around, and while I collected various hints and suggestions, nothing worked — until I found the definitive fix.

The setup used when writing this: a KVM virtual machine running in Proxmox, Debian, WordPress, and PHP. The specific versions do not matter — this solution works on current setups as well.

Here are the common causes worth checking first:

• Wrong file/folder permissions on WordPress Your entire WordPress directory (including subdirectories and files) must be owned by the web server user, e.g. www-data for Apache or nginx for Nginx — not root.
• Incorrect chmod settings Run sudo chmod -R 0755 /path/to/wordpress/ to fix permission issues.
• Plugins attempting to fix scheduling Several plugins claim to fix this, but they typically only handle post scheduling — not backup tasks or other cron jobs. None of them fixed the root issue.
• Wrong server time, date, or timezone Install ntp (or systemd-timesyncd) on your Linux server to keep the clock synchronized. Make sure to run it at least once after installation.
• Mismatched timezone between server and WordPress In WordPress Settings, set the date, time, and timezone to exactly match your server configuration.
• Conflict with a plugin or theme For troubleshooting, disable all plugins and custom themes to isolate the issue.

The definitive fix#

After weeks of searching, the solution turned out to be a single line added to wp-config.php.

Short version#

Add this line to wp-config.php, just before the /* That's all, stop editing! Happy blogging. */ comment:

define('ALTERNATE_WP_CRON', true);

Restart your web server and scheduling will work again.

Why this works#

If your WordPress is running behind a router or firewall (such as pfSense or OPNsense), missed schedules may not be caused by a problem on the machine itself — they are caused by your network architecture.

WordPress runs scheduled tasks by making an HTTP request to itself via wp-cron.php. If your router or firewall blocks loopback requests (requests from the server to itself), WordPress can never execute those scheduled tasks.

Setting ALTERNATE_WP_CRON to true changes how WP-Cron is triggered: instead of relying on a loopback HTTP request, it uses a redirect-based mechanism that bypasses the loopback restriction.

Security note (shared hosting or Apache)#

Enabling ALTERNATE_WP_CRON adds a doing_wp_cron query string parameter to some URLs. To prevent any potential abuse, add the following rewrite rule to the .htaccess file at the root of your WordPress site:

Options +FollowSymLinks
RewriteEngine On
RewriteCond %{QUERY_STRING} (^|&)doing_wp_cron= [NC]
RewriteRule (.*) /$1? [R=301,L]

This strips the parameter from the URL, preventing it from being visible or exploited externally.