Not Acceptable

An appropriate representation of the requested resource /wp/wp-admin/options-permalink.php could not be found on this server.

Additionally, a 404 Not Found error was encountered while trying to use an ErrorDocument to handle the request.

I was getting below error, I believe it is to do with mod_security.

I have tested this by putting below entry in my .htaccess, But unfortunalty does not work for me, so raise a support ticket and disabled with hosting provider.

<IfModule mod_security.c>
  SecFilterEngine Off
</IfModule>

You sure can do it manually. I am trying to find out why the page is blank too, but in the mean time I have manually altered the setting in PHPMyAdmin.

1. Go in to PHPMyAdmin
2. In the sidebar on the left select wp_options
3. Go to Page number: 2
4. click the pencil on the link with permalink_structure
5. In the big box next to option_value and input /%postname%