Very Big Problem in: http://validator.w3.org

Dear Sir,

I am a webmaster, i am using your site regularly for valid html validations.
I am facing problem from your site: http://validator.w3.org from few months.
this is not working properly.

Your HTML Markup Valida-tors is not working properly,
Errors are when i uploading a files:

1.
Proxy Error

The proxy server received an invalid response from an upstream server.
The proxy server could not handle the request POST /check.

Reason: Error reading from remote server

Apache/2 Server at validator.w3.org Port 80
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2.
Bad Gateway

The proxy server received an invalid response from an upstream server.
Apache/2 Server at validator.w3.org Port 80
---------------------------------------------------

Kindly try to find and resolve this problem.

Thanks
Sanjay Kumar
from: India, Delhi.