How to Fix Apache .htaccess Error

In this tutorial, you'll learn about How to Fix Apache .htaccess Error. We cover key concepts, practical examples, and best practices to help you understand and apply this topic effectively.

Apache returns 500 Internal Server Error when .htaccess is present, or the directives in .htaccess have no effect — the AllowOverride directive is not set correctly for the document root.

The Problem

[2026-06-24 10:00:00] [alert] [client 10.0.0.1]
/var/www/html/.htaccess: Invalid command 'RewriteEngine',
perhaps misspelled or defined by a module not included in the server configuration

Step-by-Step Fix

Step 1: Enable AllowOverride

# /etc/apache2/sites-available/example.com.conf
<Directory /var/www/html>
    Options Indexes FollowSymLinks
    AllowOverride All
    Require all granted
</Directory>

Step 2: Verify mod_rewrite is enabled

sudo a2enmod rewrite
sudo systemctl reload apache2

Step 3: Check .htaccess syntax

# Correct .htaccess
RewriteEngine On
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule ^(.*)$ index.php?url=$1 [QSA,L]

# Prevent directory listing
Options -Indexes

# Set default charset
AddDefaultCharset UTF-8

Step 4: Enable .htaccess logging

# /etc/apache2/apache2.conf
LogLevel alert:trace5

Step 5: Test configuration

sudo apachectl -t

Expected: Syntax OK

Prevention Tips

• Use <Directory> blocks in virtual host configs instead of .htaccess for performance
• Set AllowOverride All only when necessary (prefer AllowOverride None in production)
• Enable only the required Apache modules for your .htaccess directives
• Keep .htaccess files out of version control (add to .gitignore)

Common Mistakes with htaccess error

1. Forgetting that lazy evaluation defers computation until the value is forced, causing space leaks with unevaluated thunks
2. Using return to exit a function early instead of wrapping a pure value in the monad
3. Mixing let bindings with <- bindings in do notation, producing type errors

These mistakes appear frequently in real-world APACHE code. DodaTech's contributors have identified these patterns through analysis of open-source projects and production systems.

Practice Exercise

Write a pure function that safely divides two integers using Maybe, then test it with edge cases like division by zero and negative numbers.

This exercise reinforces the concepts covered in this guide. Try implementing it before checking online solutions.

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