Enabling WordPress debug mode to diagnose errors

WordPress suppresses all PHP errors by default to prevent sensitive information from showing to site visitors. Debug mode re-enables error logging to a file so you can see what's going wrong without exposing errors to the public.

What debug mode does

With WP_DEBUG enabled, WordPress:

• Logs PHP errors, warnings, and notices to wp-content/debug.log
• Helps identify which plugin or theme is throwing errors
• Shows deprecation notices from outdated code
• Reveals undefined variables and missing functions

Enable debug mode

1. Log in to cPanel → File Manager
2. Navigate to your WordPress installation root (usually public_html)
3. Open wp-config.php and find the line: define( 'WP_DEBUG', false );
4. Replace that section with:

define( 'WP_DEBUG', true );
define( 'WP_DEBUG_LOG', true );
define( 'WP_DEBUG_DISPLAY', false );
@ini_set( 'display_errors', 0 );

Save the file. WordPress now writes errors to wp-content/debug.log instead of showing them to visitors.

Read the debug log

1. In File Manager, navigate to public_html/wp-content/
2. Open debug.log
3. Look for lines with PHP Fatal error, PHP Warning, or PHP Notice
4. Each error shows the file path and line number where the problem occurred

A typical error:

[06-Jun-2026 14:55:32 UTC] PHP Fatal error: Uncaught Error: Call to undefined function
woocommerce_cart() in /home/user/public_html/wp-content/themes/mytheme/functions.php:87

This tells you the theme's functions.php at line 87 is calling a WooCommerce function that doesn't exist-WooCommerce may be deactivated or not installed.

Disable debug mode when done

After diagnosing your issue, set WP_DEBUG back to false:

define( 'WP_DEBUG', false );

Leaving debug mode enabled indefinitely fills up disk space as the debug.log file grows and may expose paths when errors occur in certain edge cases.

Query Monitor plugin

For diagnosing performance issues, slow database queries, or plugin conflicts in the browser, install the free Query Monitor plugin. It adds a debug bar to the WordPress admin showing queries, hooks, HTTP requests, and PHP errors in real time-without touching wp-config.php. Deactivate it when not needed.

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