Debugging a 500 Server Error in Laravel (Nginx + PHP-FPM)

When Laravel throws a 500, you’ll need to trace it through three layers: Laravel itself, Nginx, and PHP-FPM. Here’s where to look and how to pinpoint the issue.

1. Turn on Laravel Debug

  1. Open your project’s .env file.
  2. Set APP_DEBUG=true APP_ENV=local
  3. Save and reload your page.
    – You should now see a detailed stack trace instead of the generic 500 page.

2. Inspect Laravel Logs

Laravel logs errors in storage/logs. Usually you’ll find:

cd /home/mailivery/mailivery
ls storage/logs
tail -n 50 storage/logs/laravel.log

– Look for the latest timestamped file (laravel-YYYY-MM-DD.log).
– Errors, exceptions, SQL problems and failed queue jobs all land here.

3. Check Nginx Error Logs

By default Nginx writes to:

/var/log/nginx/error.log

Or, if you have a per-site config:

/var/log/nginx/your-site-error.log

Tail it live as you refresh:

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

Common culprits: wrong root path, missing index.php, bad fastcgi_pass.

4. Review PHP-FPM Logs

Depending on your PHP version, you’ll have one or more of:

/var/log/php7.4-fpm.log
/var/log/php8.1-fpm.log

Or check the pool-specific log in /etc/php/8.1/fpm/pool.d/www.conf for error_log.

Tail it:

sudo tail -f /var/log/php8.1-fpm.log

Look for PHP parse errors, call-stack dumps, or FPM pool failures.

5. Verify File & Folder Permissions

Laravel needs write access to storage/ and bootstrap/cache:

cd /home/mailivery/mailivery
sudo chown -R www-data:www-data storage bootstrap/cache
sudo chmod -R 750 storage bootstrap/cache

If PHP-FPM runs as a different user, swap www-data accordingly.

6. Final Tips & Next Steps

  • Use Laravel’s Log::info() or dd() to pinpoint logic errors.
  • Install Laravel Telescope or Sentry for deeper runtime telemetry.
  • If you suspect opcache or stale files, restart PHP-FPM: sudo service php8.1-fpm restart
  • For systemd-enabled servers, view FPM via journalctl -u php8.1-fpm.

Once you find the first error line in Laravel’s log or PHP-FPM’s stack, you’ll know exactly what to fix. Happy debugging!

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