403 Permissions error after changing permalinks

Solution 1:

1. Delete .htaccess
2. Upload a blank .htaccess
3. Set the permissions to 666
4. Change the permalink structure to what you want.
5. Set the permissions back to 644

Solution 2: Edit .htaccess

If WordPress is in a directory /blog:

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

If WordPress is in the root:

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

Solution 3:

Add the following lines above the WordPress generated code:

Options -Indexes
Options +FollowSymLinks

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