Fix Website "500 Internal Server Error"

Understanding 500 Errors

A generic "something went wrong" error. The real cause is in logs.

Step 1: Check Error Logs

# Nginx
sudo tail -f /var/log/nginx/error.log

# Apache
sudo tail -f /var/log/apache2/error.log

# PHP-FPM
sudo tail -f /var/log/php*-fpm.log

# Application logs (WordPress, Laravel, etc.)
sudo tail -f /var/www/your-site/storage/logs/laravel.log

Common PHP Causes

Parse Errors

Syntax errors in code:

php -l /path/to/suspicious-file.php

Memory Limit Exhausted

Increase in php.ini:

memory_limit = 256M

Caching Issues

# Clear opcache
sudo systemctl restart php*-fpm

# Clear application cache (Laravel)
php artisan cache:clear
php artisan config:clear

File Permissions

# WordPress
sudo chown -R www-data:www-data /var/www/wordpress
sudo find /var/www/wordpress -type d -exec chmod 755 {} ;
sudo find /var/www/wordpress -type f -exec chmod 644 {} ;

WordPress Specific

Increase memory in wp-config.php:

define('WP_MEMORY_LIMIT', '256M');

Disable plugins via FTP:

mv /var/www/wordpress/wp-content/plugins/plugin-name /var/www/wordpress/wp-content/plugins/plugin-name-disabled

Enable PHP Error Display (Temporary)

# At top of index.php
ini_set('display_errors', 1);
error_reporting(E_ALL);