Multisite not working on a vanilla install of WP

HI there,

I have a vanilla install of WP here:
http://schoolsy.co.uk

I have installed only the following plugins - all of which are WPMU Dev plugins:
WPMU DEV Dashboard
Domain Mapping
Pro Sites

My .htaccess file looks has this added:

define( 'WP_ALLOW_MULTISITE', true );

define('MULTISITE', true);
define('SUBDOMAIN_INSTALL', true);
define('DOMAIN_CURRENT_SITE', 'schoolsy.co.uk');
define('PATH_CURRENT_SITE', '/');
define('SITE_ID_CURRENT_SITE', 1);
define('BLOG_ID_CURRENT_SITE', 1);

define('SUNRISE', 'on');

---

My .htaccess file looks like this:

# BEGIN WordPress

<IfModule mod_rewrite.c>
RewriteEngine On
RewriteBase /
RewriteRule ^index\.php$ - [L]

# add a trailing slash to /wp-admin
RewriteRule ^wp-admin$ wp-admin/ [R=301,L]

RewriteCond %{REQUEST_FILENAME} -f [OR]
RewriteCond %{REQUEST_FILENAME} -d
RewriteRule ^ - [L]
RewriteRule ^(wp-(content|admin|includes).*) $1 [L]
RewriteRule ^(.*\.php)$ $1 [L]
RewriteRule . index.php [L]
</IfModule>

# END WordPress

---

I've moved sunrise.php to wp-content/

I cannot however visit any site that I'm creating as multisite. If I create new site and visit it I get a browser error. For example in Chrome I see:

This site can’t be reached

test.schoolsy.co.uk’s server DNS address could not be found.
Try:
Reloading the page
Checking the connection
Checking the proxy, firewall, and DNS configuration

---

Please could you offer some support as to why this might be happening.

Thanks.

BTW - the domain was registered about 3 hours ago, but I can visit the 'main' site so I know that the DNS is propagated properly.

I have enabled support access to the site also.