In the past twenty-four hours, it seems as if Google sent out a message to thousands, maybe hundreds of thousands, of site owners, that there is a problem with their site.
Typically, you never, ever want to ignore a webmaster tools notification but in this case, you can: it appears the messages were sent in error.
Google told these webmasters that “Googlebot can’t access your site“, that the site had connection failures and Google was unable to access your site.
Google’s Matt Cutts wrote in the thread that this seems like an error on Google’s side. He said:
Hey everyone, please don’t worry about this message at this point. Enough people are getting this message that I suspect it’s an issue on our end.
I’ve got an email out to our webmaster tools team, and we’ll figure out what’s going on. Thanks.
John Mueller of Google is asking webmasters to post example URLs so they can fix the issue.
We’ve been monitoring our Webmaster Tools accounts throughout this issue and while we have received these messages by email for some of our client’s websites, the WMT console does not show the error on these sites. It definitely does look like a Google issue, so we’re keeping an eye on this issue while carrying on as normal.
[Update: 27 April] Google is reporting the issue has been fixed, but some WMT users are still reporting issues. We will continue to monitor the situation and update this post if needed.