Find answers, guides, and tutorials to optimize your images.

Error Codes

Updated on November 21, 2018

Why am I receiving a "Not Found" error?

A Not Found error occurs when Optimus cannot find the image in your server's filesystem. A few common causes of this include:

  • If an image and ALL of its variations are removed from the filesystem however it still exists in the database, Optimus will return an internal error message. To verify if this is the case, check your Media Library and look for broken images like the following.

Once you've identified these images, simply delete them so that they are removed from the WordPress database.

  • Since WordPress 3.5, the Media Uploader settings have been removed from the WP admin dashboard however are still configurable by defining their path in your wp-config.php file. For example:

    define( 'UPLOADS', 'wp-content/'.'files' );

This would place the uploads directory in wp-content/files rather than the default location wp-content/uploads. Check that you have properly defined your uploads path so that Optimus can properly reference and optimize your images.

  • If you are using a plugin such a WooZone then you might experience this error if you are delivering images directly from Amazon's CDN instead of downloading them directly to your server. The following settings will deliver images directly from Amazon's CDN, therefore, there is no need to optimize them with Optimus and you will receive a Not found error if you try to.

If you would rather deliver the images directly from your server and optimize them with Optimus you will need to set the "Remote amazon images" feature to NO.

Why am I receiving error code 0?

An error code 0 is usually related to a timeout configuration issue on your origin server. The image may not be able to be optimized in the allotted time that is defined in the timeout setting therefore you will receive a code 0 similar to this.

To fix this, you must increase the max_execution_time in your php.ini file. It is likely it is currently set at 30 seconds, however you will want to increase this value so that the system does not timeout during the optimization of large images. We recommend the following setting:

max_execution_time = 180

Alternatively, if setting the max_execution_time does not work, your firewall may be blocking the Optimus servers. In that case, try whitelisting the prefix on your origin server.

Why am I receiving error code 204?

Error code 204 appears when there is an error with the image or it is broken. Try re-exporting the image or rebuilding the image to fix this error.

Why am I receiving an "Internal Error"?

There is one main reason you could be receiving an Internal Error.

  • Any PHP error is also shown as internal error. There may be a configuration conflict with another plugin or your theme's files.

To further debug this issue, modify your wp-config.php file to reflect the following.


define('WP_DEBUG', false);


define('WP_DEBUG', true);
define('SAVEQUERIES', true);
define('WP_DEBUG_LOG', true);
define('WP_DEBUG_DISPLAY', true);
error_reporting(E_ALL | E_STRICT);
KeyCDN uses cookies to make its website easier to use. Learn more