Client cannot access web site

We have a client that cannot access their web site without the www in front of the address. They get an error whenever they try to access it without www. This is an issue because of how a third party links to their site (which is without the www).

I have set the domain to always use www in the panel and I’ve also set the plain domain to redirect to the www domain in htaccess. Still when the client is sent to the non-www address they get an error that the site can’t be displayed. The redirect does not work for them for some reason.

I’m at a loss as to tell them what to do. They are on Windows. The domain in question is It works fine for me and always has. It’s just the users at the client’s company that are having trouble. Any ideas what I can tell them to do to fix this?