How to check for errors in WordPress

When a WordPress site fails, it often displays a blank screen (the “White Screen of Death”) or a generic “500 Internal Server Error.” On the mybox infrastructure, these errors usually point to a conflict between plugins, an incompatible PHP version, or a failed update.

To resolve these issues, you must bypass the generic error page and look at the specific diagnostic data generated by the WordPress core.

Activating WordPress Debug Mode (WP_DEBUG)

WordPress has a built-in “hidden” diagnostic tool called WP_DEBUG. Activating it forces the website to display the exact file and line of code causing the problem.

1. Log in to your account via FTP or SFTP.
2. Locate the wp-config.php file in your website’s root directory (usually public_html).
3. Open the file and look for this line: define( 'WP_DEBUG', false );
4. Change false to true: define( 'WP_DEBUG', true );
5. Save the file and upload it back to the server.

Understanding Diagnostic Information

Once debug mode is active, refresh your website. You will see text-based messages instead of a blank screen. It is important to distinguish between “noise” and critical failures:

• Deprecated / Warning: These indicate that some code is outdated. While they should eventually be fixed, they do not bring your site down. You can usually ignore these during emergency troubleshooting.
• Fatal Error: This is a critical failure. The error message will typically include a file path like: .../wp-content/plugins/plugin-name/filename.php This tells you exactly which plugin is causing the crash.

Practical Troubleshooting Steps

1. Deactivating a Faulty Plugin

If a “Fatal Error” points to a specific plugin and you cannot access your WordPress dashboard:

1. In your FTP client, go to wp-content/plugins/.
2. Find the folder for the problematic plugin.
3. Rename the folder (e.g., change contact-form-7 to contact-form-7-old).
4. WordPress will automatically “lose” the plugin and allow the rest of the site to load.

2. Fixing a “Stuck” Update

If your site shows a message saying “Briefly unavailable for scheduled maintenance,” a previous update may have failed.

1. Check your root directory (public_html) for a file named .maintenance.
2. Delete this file. This will immediately take the site out of maintenance mode.

Distinction Block

WP_DEBUG vs. PHP Display Errors WP_DEBUG is a WordPress-specific setting that manages how the CMS handles its internal logs. PHP Display Errors (set via ini_set) is a server-level setting. For WordPress sites, always prioritize using WP_DEBUG as it provides more context regarding plugins and themes.

Practical Implications

• Security: Never leave WP_DEBUG set to true on a live site once the issue is fixed. Revealing your file structure can be a security risk.
• Version Check: If you see “Fatal Errors” after a mybox infrastructure update, check if your PHP version in the panel matches the requirements of your WordPress version.
• Log Files: If you don’t want errors to appear to visitors, you can use define( 'WP_DEBUG_LOG', true ); in wp-config.php. This saves the errors to a file named debug.log inside the wp-content folder instead of displaying them on the screen.

Summary

Troubleshooting WordPress on mybox is a process of elimination. By enabling WP_DEBUG, identifying the “Fatal Error,” and temporarily renaming conflicting plugin folders, you can restore your website’s functionality without needing to reinstall the entire system.