HTTP request status Fails

After I installed Drupal and go into my administer page, I get a notice: One or more problems were detected with your Drupal installation. Check the status report for more information.

And here is the problem...

HTTP request status Fails
Your system or network configuration does not allow Drupal to access web pages, resulting in reduced functionality. This could be due to your webserver configuration or PHP settings, and should be resolved in order to download information about available updates, fetch aggregator feeds, sign in via OpenID, or use other network-dependent services.

Does anybody know what this means?