404 Not Found
Diagnose a 404 Not Found by checking the URL, deleted files, broken routes, redirects, permalinks, and server configuration.
WordPress Troubleshooting
Fix WordPress errors involving 500 responses, 502 gateways, database connections, plugins, themes, wp-config.php, PHP, and logs.
What breaks in WordPress
WordPress requests move through browser, DNS, CDN/cache, web server, PHP runtime, WordPress core, plugins, theme code, and the database. A visitor can only retry, test another browser, or report details. A site owner should identify the failing layer before editing plugins, .htaccess, or wp-config.php.
Start here by symptom
| Symptom | Likely layer | Best path |
|---|---|---|
| Error establishing a database connection | DB credentials, host, or service health | Database connection error |
| 500 after plugin/theme update | Plugin, theme, PHP fatal, or .htaccess | WordPress 500 |
| 502 or gateway error | PHP-FPM, hosting limit, proxy, CDN, overloaded plugin | WordPress 502 |
| wp-admin unavailable | Plugin/theme/PHP issue | Disable plugins without admin |
| Credentials may be wrong | wp-config.php | Repair database settings |
Do not make it worse
Back up files and database before renaming plugin folders, editing .htaccess, or changing wp-config.php. Preserve the original value, screenshot, or copied file. If a host panel controls database credentials, update the panel and file together rather than guessing from memory.
Escalation template
URL affected:
Time and timezone:
Error shown:
Recent plugin/theme/PHP/cache changes:
Does wp-admin load:
Relevant PHP/nginx/Apache/database log line:
What was rolled back or tested:Related topics
Use database errors for DB credentials and health, HTTP errors for status-code diagnosis, and nginx troubleshooting when the visible failure is a gateway or upstream error.
Errors
500 Internal Server Error
Find the cause of a 500 Internal Server Error by checking logs, recent deploys, plugins, PHP failures, permissions, and rollback options.
502 Bad Gateway
Diagnose a 502 Bad Gateway by checking the proxy, CDN, upstream app, PHP-FPM, timeouts, and server logs before changing DNS.
Error Establishing a Database Connection
Fix the WordPress database connection error by checking wp-config.php, database credentials, MySQL/MariaDB health, and hosting changes.
500 Internal Server Error in WordPress
Fix a WordPress 500 error by checking plugins, themes, PHP memory, debug logs, .htaccess, permissions, and recent changes.
502 Bad Gateway in WordPress
Troubleshoot a WordPress 502 by checking PHP-FPM, overloaded plugins, theme changes, cache/CDN layers, hosting limits, and logs.
Guides
Disable plugins in WordPress without admin access
Disable WordPress plugins through files or database access when wp-admin is unavailable because of a 500, 502, or database error.
Check access and error logs for HTTP failures
Learn how to inspect access logs, error logs, status codes, timestamps, upstream failures, and recent changes during HTTP outages.
Roll back a website change safely
Use a safe rollback workflow for website errors by preserving evidence, restoring the smallest change, and verifying recovery.
Fix broken redirects, permalinks, and rewrite rules
Repair redirects, permalink rules, rewrite configuration, and route mismatches that cause 404s or redirect loops after site changes.
Trace 502 through proxy, CDN, and upstream layers
Trace a 502 Bad Gateway across browser, CDN, reverse proxy, origin server, upstream app, and logs to find the failing layer.
Repair WordPress database settings in wp-config.php
Check and repair WordPress database settings in wp-config.php, including database name, user, password, host, charset, and table prefix.
Check MySQL or MariaDB health for WordPress
Verify MySQL or MariaDB service health, connection limits, credentials, database availability, and hosting status for WordPress errors.
Check WordPress file permissions
Check WordPress ownership and permissions when uploads, plugins, themes, cache files, or PHP includes fail after a migration or deploy.
Check WordPress PHP version, extensions, and memory
Check PHP version, required extensions, memory limits, and fatal errors when WordPress fails after hosting, plugin, theme, or core changes.
Clear WordPress page, object, and CDN cache safely
Clear WordPress cache layers in the right order so stale pages, object cache, or CDN responses do not hide the real fix.
Enable WordPress debug log safely
Turn on WP_DEBUG_LOG without displaying errors publicly so WordPress 500, white screen, plugin, theme, and PHP failures leave evidence.
Fix WordPress white screen without wp-admin access
Recover from a WordPress white screen when the admin area is unavailable by checking debug logs, plugins, themes, PHP memory, and recent changes.
Restore WordPress from backup safely
Restore WordPress files and database carefully after a failed update, bad migration, broken plugin, or damaged wp-config.php change.
Understand wp-config.php for WordPress troubleshooting
Use wp-config.php as the starting reference for database credentials, debug logging, salts, table prefixes, and environment-specific WordPress settings.