WordPress 404 Error and Permalink Fix

Quickest Fix: Flush Permalinks

1. WordPress Admin - Settings - Permalinks
2. Click Save Changes without editing anything
3. This regenerates the htaccess file automatically

Manual htaccess for WordPress

# BEGIN WordPress
<IfModule mod_rewrite.c>
RewriteEngine On
RewriteBase /
RewriteRule ^index\.php$ - [L]
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule . /index.php [L]
</IfModule>
# END WordPress