WordPress — Express troubleshooting

Incident-focused WordPress reference for logs, plugins, themes, database, WP-CLI, cron, permalinks, SMTP, permissions and 500/critical errors.

Files & paths

Configuration — wp-config.phpContains DB access, salts and debug constants.
Plugins — wp-content/plugins/A failing plugin can be disabled by renaming its folder, carefully.
Themes — wp-content/themes/Keep a compatible default theme available as fallback.
Uploads — wp-content/uploads/Check disk space, permissions and URLs before blaming Media Library.

Enable debug — define('WP_DEBUG', true);Enable temporarily during diagnostics.
Log errors — define('WP_DEBUG_LOG', true);Normally writes to wp-content/debug.log.
Hide display — define('WP_DEBUG_DISPLAY', false);Avoids exposing detailed errors to visitors.
PHP/web log — error_log / logs FPM / logs Apache ou NginxFor HTTP 500, server logs are often more precise than WordPress UI.

List plugins — wp plugin listShows plugin status and versions from shell.
Deactivate plugin — wp plugin deactivate nom-pluginCleaner than renaming if WP-CLI is available.
Deactivate all — wp plugin deactivate --allStrong diagnostic action; plan application impact.
Switch theme — wp theme activate twentytwentysixOnly if a compatible fallback theme is installed.

Database check — wp db checkChecks access and logical table state.
Table prefix — $table_prefixConfirms the table prefix expected by the site.
WordPress URL — wp option get siteurlCompare siteurl and home during redirect/migration issues.
Home URL — wp option get homeMismatch can cause redirects or incorrect links.

Cron events — wp cron event listShows overdue, frequent or unexpected tasks.
Run due cron — wp cron event run --due-nowMay execute many tasks; use with impact awareness.
WP-Cron disabled — define('DISABLE_WP_CRON', true);If enabled, an external scheduler must invoke wp-cron.php.
Cron loops — Search hooks qui se replanifient anormalementCorrelate with PHP logs and database load.

Flush permalinks — wp rewrite flushDo not run on every request; use after rewrite changes.
List rewrite rules — wp rewrite list | head -50Useful to verify expected routes.
Object cache — wp cache typeDepending on version, may identify active cache implementation.
HTTP status — curl -I https://exemple.fr/page/Compares public behavior without browser state.

wp_mail — Depends on PHP configuration or an SMTP plugin. A form can validate successfully while delivery fails.
SMTP — Use an appropriate authenticated service with diagnostic logs. Keep message ID or provider trace for diagnostics.
SPF/DKIM/DMARC — Check the domain used in From and Return-Path. Incorrect sending identity can cause spam or rejection.
WP-CLI mail test — wp eval "var_dump(wp_mail('admin@example.com','Test BOAI','Test'));"true only means WordPress handed the message to the configured transport.

Check logs first — PHP-FPM / Apache / Nginx / debug.logThe critical error page often hides the full root cause.
Memory — memory_limit + WP_MEMORY_LIMITPHP/FPM limits may override WordPress constants.
Failing plugin — Rename one plugin directory at a time. Change one variable at a time.
Recovery mode — A WordPress recovery link requires a working administrator email address. Useful to isolate plugins without FTP, but relies on email delivery.