Only use if you are an advanced user.
There are some cases in which the default WordPress rewrite rules for permalinks may not work. For example, when you have other settings defined in .htaccess files located in subfolders.
To exclude these subfolders from the WordPress rewrite rules, you should edit the .htaccess file and change the bold line below:
# BEGIN WordPress
RewriteEngine On
RewriteBase /
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule . /index.php [L]
# END WordPress
to
RewriteRule ./ /index.php [L]