Why Googlebot can't access my site?

Hi all, I am in a problem with my blog. In my google.com/webmasters/tools I got a message that “Googlebot can’t access your site, Over the last 24 hours, Googlebot encountered 1 errors while attempting to connect to your site. Your site’s overall connection failure rate is 33.3%.”

There was some Recommended action

Verify that the web service software for your site is installed and running properly.
Verify that your firewall or server are not blocking googlebot's access to your site.
Verify that all scripts that run on your site have proper permissions to run.
Verify that your site has proper permissions to access the pages of your site.
Using Webmaster Tools, find a day with a high error rate and examine the logs for your web server for that day. Look for errors in the logs for that day and fix the causes of those errors.
Your site may be overloaded. Talk with your hosting provider about either reconfiguring your web server or allocating more resources to your web server.
If your site redirects to another hostname, another possible explanation is that a URL on your site is redirecting to a hostname that has one or more of the problems listed above.

After you think you’ve fixed the problem, use Fetch as Google to verify that Googlebot can properly access your site.

I communicate with my hosting provide, he said me “Its a problem of chmode or .htaccess or robot.txt file” but everything was well! Please help me to solve this problem. I am worried about my blog.

You’ve had 1 error in 3 tries. Perhaps your host hiccuped, perhaps Google did. Either way it’s not enough to go on yet so as Google suggests, use the Fetch tool to insure the problem does not persist.

Thanks for quick replay but I to know details more. I am new in blogging so can you suggest me how to fetch in google (How many link should fetch in google)?

Google will [and is already] fetching your site automatically to update it. The more you publish to it, the more often it will come back.

When you have a specific issue you need to debug such as this one you can use the Fetch as Google option to test. This is explained @ http://support.google.com/webmasters/bin/answer.py?hl=en&answer=158587

Thanks, I get it!

Try to resolve the DNS drawback 1st, hope Google can rank your web site again!