Cant figure out this intermitten problem DNS 500

Some things to try

• Look for matching error messages in the Web server log files
  
• Check server load statistics (for CPU, memory and disk) and examine the logs for network timeouts
  
• Check the .htaccess, web.config or similar configuration files for any recent modifications that may have introduced logic errors
  
• Check the site's file and folder permissions (particularly if the errors occur only for requests to certain pieces of content)