Perhaps these people work in large companies and have a bad setting of proxy server in their browsers, or the company proxy blocks your domain name, for some reasons…
(in the second case you have nothing to do, they won’t be able to open your site)
I’m using Chrome and I can see your site.
Maybe it was a temporary problem due to bad DNS propagation, but I think that it was a problem of your hosting provider.
If the subsite is contained in a subfolder and points to a separate database, you have to think to it as a completely different website from yours.
You can change logo and widget in the theme administration page.
Maybe it’s a problem of the mobile browser, if it works fine on desktops.
Did you try it with different browsers and OS (i.e. Android, IOS, Windows Phone…)?
