WordPress Troubleshooting Intermediate

WordPress troubleshooting guide-systematic diagnosis

Systematically troubleshoot WordPress issues: enable debug mode, isolate plugins and themes, check logs, and resolve common problems.

UnderHost NOC Network Operations

11 min read Updated June 2026

On this page

Enable WordPress debug mode
Plugin and theme isolation
Common issues and fixes
Troubleshooting checklist

Most WordPress problems stem from plugin conflicts, memory limits, PHP errors, or misconfigured settings. A systematic approach finds the cause faster than guessing.

Enable WordPress debug mode

Add to wp-config.php before "That's all, stop editing":

define('WP_DEBUG', true);
define('WP_DEBUG_LOG', true);
define('WP_DEBUG_DISPLAY', false);  // Hide from visitors

Errors log to wp-content/debug.log. Read it via File Manager or SSH:

tail -50 /home/user/public_html/wp-content/debug.log

Plugin and theme isolation

Safe mode — disable all plugins without admin access:

File Manager → navigate to wp-content/
Rename plugins folder to plugins-disabled
Reload your site — if error clears, a plugin caused it
Rename back to plugins, then rename individual plugin folders to isolate

Switch to default theme: Rename your active theme folder — WordPress falls back to Twenty-x default.

Common issues and quick fixes

Symptom	First thing to check
White screen	Enable WP_DEBUG, check debug.log
"Error establishing database connection"	Verify wp-config.php credentials
Cannot log in	Clear cookies, try incognito mode
Redirect loop	Check Settings → General — both URLs must match
500 error after update	Disable last-updated plugin, increase memory limit
Images not uploading	Check wp-content/uploads/ permissions (755)