"Suggest URL" resulting in Proxy error during these days!

"Suggest URL" resulting in Proxy error
Hi everyone.

I'm trying to suggest an URL (category: Society: Subcultures: Geeks and Nerds: News and Media) and when I click "Suggest URL" I'm always receiving this error:

Proxy Error

The proxy server received an invalid response from an upstream server.
The proxy server could not handle the request GET /cgi-bin/add.cgi.

Reason: Error reading from remote server

I tried Firefox and Internet Explorer for Windows , and I keep getting the same error.

Any idea?

Thanks.