There seems to be connection issues for players in the Mid-west US.

Here is the blue post for people that can not connect to the oBoards:

We are aware there are currently some kind of Internet issues preventing some of our players from connecting to certain realms - and possibly our main website.

We are looking into this at the moment and will get back with information as soon as we can.

Please feel free to post in this thread.

We do appreciate your patience.

[Editors Note: The problem has since been resolved, but if you're still experiencing issues, please post in the official forums so Blizzard is made aware!]