Sub Domain Problems?

[BlkSwanPres]

I have a sub domain setup that one of my webmasters has trouble accessing. We cannot figure out why it keeps coming up as server unavailable when I can give him a direct link to it on the server and he can see it fine. Only when he uses the sub domain name he has problems. What I was wondering is if I set it up wrong, I set it up like I would a new account, just under the domain name I put sub.domain.com, instead of just domain.com, Could this be causing my problems, should I have done this another way? Is there something else I need to do?

[acer2k]

Yes, we are experiencing the same issue. Everything looks fine.