Why am I getting authentication_redirect_to_virtual_host error?

I am calling a web service that is online.

Sometime (not all the times), it crashes and gives me the following exception:

Redirect (authentication_redirect_to_virtual_host)

You are being redirected to the authentication virtual host.

For assistance, contact your network support team. 

But I can open the web service from the browser normally.

Why am I getting this error? and how to solve it?

Note that I am passing the correct credentials to the web servi开发者_StackOverflow社区ce.

any chance you are using a blue coat proxy server? That was an issue I ran into and it required the network team to create a rule to allow traffic from the webserver to the web service/REST i was accessing.