I'm not sure if this is caused by Pro Sites install, or

Hi, I'm not sure if this is caused by Pro Sites install, or a multisite set up mistake I've made.

I'm running a subdirectory based Multisite using Pro Sites.

For example when one tries to access the new blog without "www" via http://weddingday.co.jp/keigoandalisaun
I get a 404page.
How can I get the page to display correctly?
http://www.weddingday.co.jp/keigoandalisaun displays just fine

Thank you in advance,
I love our service!
Keigo