HTTP request status Fails

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.

Started getting the above warning this morning when logged into admin, site was suddenly slow to load. I currently have a Hostgator account!

Can anyone suggest a solution or instruction.

Appreciate the help.
mcaul