Over the last 24 hours, Googlebot encountered 128 errors while attempting to connect to your site. Your site's overall connection failure rate is 8.0%.
You can see more details about these errors in Webmaster Tools.
- 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.
After you think you've fixed the problem, use Fetch as Google to verify that Googlebot can properly access your site.
Google Web Master also said we have a lot of 404 not found errors, is that caused the problem?
Any information will be helpful.