Chapter 11: Application Hosting — WordPress, Flask and Express

Common Mistakes I See Students Make

By Ravindra Bagale · Last updated: 25 September 2026

• Installing WordPress before attaching an Elastic IP — the site breaks after stop/start.
• Wrong ownership of WordPress files (not www-data/apache) → plugins and uploads fail.
• Forgetting AllowOverride All / a2enmod rewrite → permalinks give 404.
• Skipping the security salts in wp-config.php.
• Running Flask with app.run(debug=True) in production — debug mode can allow remote code execution.
• Wrong module path in Gunicorn (app:app vs wsgi:app) → ModuleNotFoundError in journalctl.
• Not running the command printed by pm2 startup, so apps don't come back after reboot.