Troubleshooting Customizations
If you encounter errors or issues while working with themes, templates, or other customizations, see the sections below to start troubleshooting and resolve the issue.
You can troubleshoot some custom code using the steps in Troubleshooting WHMCS API Calls and Troubleshooting Hooks.
- For more information on system themes and order form templates, see Themes and Templates.
- For general steps to troubleshoot problems in WHMCS, see Start Troubleshooting.
Hooks
During the development process, you may need to verify whether your hooks are working correctly. This can include checking whether hooks are loading properly, triggering the desired hook point, and running the expected hook code.
Order Form Templates
You may encounter the following common issues:
| Error or Issue | Cause | Next Steps |
| Pages in WHMCS are empty or content is missing. | A template file is missing or contains a syntax error. | Empty Pages |
System Themes
You may encounter the following common issues:
| Error or Issue | Cause | Next Steps |
| Pages in WHMCS are empty or content is missing. | A template file is missing or contains a syntax error. | Empty Pages |
You cannot delete the active system theme. | This error occurs when attempting to delete a theme that is the active System Theme. | Theme Deletion Errors |
The system could not create the theme. | You attempted to create a theme with a name that already exists or contains invalid characters. | Theme Editor Creation Errors |
WHMCS API Calls
During the development process, you may need to verify whether your API code is working correctly. To do this, we recommend verifying your code against our documented code examples and enabling debugging to find errors.
Last modified: 2025 July 28