Problems spawning a call to the WP-Cron system

If you're seeing an error message saying there was a problem spawning a call to the WP-Cron system on your site, this indicates a problem that is preventing cron events from running. If you can see cron events that have missed their schedule by more than a few minutes, this is almost certainly a problem you need to investigate.

What should I do?

Firstly, please do not open a support thread on the WP Crontrol plugin forum as nobody will be able to assist you there. There are better places and ways to get support for this problem.

1. Reload the page a few times to determine if the error is persistent. If the error only appears once then it may have been a temporary network connectivity problem.
2. If the error persists, make a note of the error message. Common errors are listed below with more information about what they mean.
3. Try deactivating the other plugins on your site one by one. It could be that one of them is causing a problem.
4. If your website is hosted on a managed WordPress service, contact your web host and send them the error message. They are best positioned to assist you and they've probably seen the same problem before.
5. If you're not using a managed WordPress hosting service, try searching for the error message using your favourite search engine or on the support forums of your web host.
6. If you cannot diagnose the problem, post the error message in a new thread on the main wordpress.org support forums where hopefully a volunteer can assist you.

Common errors

cURL error 6: Could not resolve domain

This means there is a problem with the DNS configuration of your domain or your server. The domain name is not pointing to a valid IP address, or your server does not have up to date DNS information.

cURL error 7: Failed to connect: Connection refused

This is a bit of a mystery error. It could relate to your HTTPS configuration, or it could be an access restriction problem (see below). This may be a temporary network connectivity problem.

cURL error 28: Operation timed out after 3000 milliseconds with 0 bytes received

This means there is a network connectivity problem preventing your server from performing "loopback" requests to itself.

cURL error 35: sslv3 alert handshake failure

This means there's a problem with your HTTPS configuration. Your server cannot securely connect to itself.

Unexpected HTTP response code: 401 or 403

This means an access control restriction such as BasicAuth, a firewall, a security or privacy plugin, some form of password protection, or an .htaccess rule is preventing your server from accessing wp-cron.php.

Unexpected HTTP response code: 404

This means the wp-cron.php file in the root of your website has been deleted. Try reinstalling WordPress from the Dashboard → Updates screen.

Unexpected HTTP response code: 500 or higher

This means an error has occurred on your server which is preventing the cron spawner from running. Check the error logs on your server.