The WHMCS application will suppress all non-critical warnings and notices and attempt to complete all requested actions in its default configuration. If an error condition is critical and the continued execution of a requested action is either detrimental or not possible, the system will display a friendly, styled error page and log the event.

You can customize the appearance of these error pages. To control how WHMCS reports and manages errors (for example, to enable error display while debugging), see Errors in WHMCS.

Error Templates #

The Twenty-One and Six system themes include default error templates. You can find them within each theme’s template directory (for example, /templates/twenty-one/) at the following filepaths:

• error/internal-error.tpl
• error/page-not-found.tpl
• error/unknown-routepath.tpl

Custom Themes #

If you create a custom theme, you can customize these pages by creating these files in your theme’s directory (for example, /templates/example/error/internal-error.tpl, where example is the directory for your custom theme).

You cannot change the dynamic content that WHMCS inserts into these files. However, your customized files can reposition that dynamic content, replace it with your own hardcoded alternative, or omit it entirely. To help reduce any further possible error paths, Smarty doesn’t process these files.

Error Template Variables #

These files can use the following variables:

Last modified: 2026 July 7