Error Message

Ok, I can’t figure out if this is my fault or if there was something wrong with the setup on the host’s side. The problem is happening even though I got several messages telling me that everything has been set up and my site is ready to go. I even uploaded an index page.
Does anyone know what this message means, or how I can fix it? Any help would be greatly apprecited.

When I type in my address, this come up:

Bad Gateway
The following error occurred:
A DNS lookup error occurred. The host was not found.

Please contact the administrator.