Server error: DNS timeout
Google couldn’t access your site because your DNS server did not recognize your hostname (such as www.example.com).
Use Fetch as Google to check if Googlebot can currently crawl your site. If Fetch as Google returns the content of your homepage without problems, you can assume that Google is generally able to access your site properly.
Check with your registrar to make sure your site is correctly set up and that your server is connected to the Internet.