I have a web service running behind a DMZ.((Demilitarised Zone)

I was able to consume my service when the web service is in my local network.
Once we removed the server from our network for our client to access our
web service. For security reasons we put the server under a DMZ.
Where as my network is partially trusted by DMZ.

But I still get the following Error.

"The underlying connection was closed. An unexpected error occurred on a

NOTE : I am able to add the web reference by typing the following.

Any help will be appriciated.