Can you visit other sites, or is it just that site?
if it is just that site, it may be down temporarily or just down completely.
It is most likely the website, here is info I found..."500 errors in the HTTP cycle
Any client (e.g. your Web browser or our CheckUpDown robot) goes through the following cycle when it communicates with your Web server:
* Obtain an IP address from the IP name of your site (your site URL without the leading 'http://'). This lookup (conversion of IP name to IP address) is provided by domain name servers (DNSs).
* Open an IP socket connection to that IP address.
* Write an HTTP data stream through that socket.
* Receive an HTTP data stream back from your Web server in response. This data stream contains status codes whose values are determined by the HTTP protocol. Parse this data stream for status codes and other useful information.
This error occurs in the final step above when the client receives an HTTP status code that it recognises as '500'.
Resolving 500 errors - general
This error can only be resolved by fixes to the Web server software. It is not a client-side problem. It is up to the operators of your Web server site to locate and analyse the logs which should give further information about the error.
Resolving 500 errors - CheckUpDown
Please contact us (email preferred) whenever you encounter 500 errors on your CheckUpDown account. We then have to liaise with your ISP and the vendor of your Web server software so they can trace the exact reason for the error. Correcting the error may require recoding program logic for your Web server software, which could take some time.
Edited by Box In A Bag, 12 December 2008 - 02:38 PM.