New Site WP Admin Login "Too many redirects"

My hosting service has setup a brand new WPMU installation for me.

While the primary URL resolves properly, I can’t access the WP-Admin login. Instead I get a “Too many redirects” error using different browsers.

I have a support ticket open with them, but perhaps someone more experienced with WPMU would know what causes this with a new site.

The new WPMU site is