Google Product Forums
Re: Googlebot did not crawl your URL because we couldn’t communicate with the DNS server
Apr 25, 2012 8:56 AM
Posted in group:
Crawling, indexing & ranking :
Your home page was cached by Google on April 18, so I assume this problem is recent.
I suggest wait a day or so and try Fetch as Googlebot, in case it was a temporary glitch.