Message from host company. What should I do?

My wordpress website is hosted by BlueHost. Today I receive the following email:
Your hostname ( could not be resolved
to an IP address. This means that /etc/hosts is not set up
correctly, and/or there is no dns entry for Please be sure that the contents of
/etc/hosts are configured correctly, and also that there is a
correct 'A' entry for the domain in the zone file.

Some or all of these problems can be caused by /etc/resolv.conf
being setup incorrectly. Please check that file if you believe
everything else is correct.

You may be able to automatically correct this problem by using the
'Add an A entry for your hostname' option under 'Dns Functions' in
your Web Host Manager.

My website is . I have never created a subdomain.

I am a little confused of what should I do. And BlueHost takes almost a week to answer tickets for VPS clients like me...They have chat for shared host, but they do not allow VPS clients to chat. Isn't absurd?

I am using WP 3.6 with Academy LMS theme/plugin.

Thanks for any help.