The remote server returned an error: (407) Proxy Authentication Required

I'm getting this error when I call a web service:

"The remote server returned an error: (407) Proxy Authentication Required".

I get the general idea and I can get the code to work by adding

myProxy.Credentials = NetworkCredential("user", "password", "domain");

or by using DefaultCredentials in code. My problem is that the call to the web service works in production without this.

It seems like there is a non code solution involving Machine.config, but what is it? At the moment I can't get to the production box's machine.config file to see what that looks like. I tried updating my machine.config as follows, but I still get the 407 error.

<system.net>
    <defaultProxy enabled="true" useDefaultCredentials="true">
        <bypasslist>
            <clear />
        </bypasslist>
        <proxy proxyaddress="myproxy:9000"
               usesystemdefault="false"
               bypassonlocal="true"
               autoDetect="False" />
    </defaultProxy>
</system.net>

Just add this to config

<system.net>
    <defaultProxy useDefaultCredentials="true" >
    </defaultProxy>
</system.net>

In following code, we don't need to hard code the credentials.

service.Proxy = WebRequest.DefaultWebProxy;
service.Credentials = System.Net.CredentialCache.DefaultCredentials; ;
service.Proxy.Credentials = System.Net.CredentialCache.DefaultCredentials;

Check with your firewall expert. They open the firewall for PROD servers so there is no need to use the Proxy.

Thanks your tip helped me solve my problem:

Had to to set the Credentials in two locations to get past the 407 error:

HttpWebRequest webRequest = WebRequest.Create(uirTradeStream) as HttpWebRequest;
webRequest.Proxy = WebRequest.DefaultWebProxy;
webRequest.Credentials = new NetworkCredential("user", "password", "domain");
webRequest.Proxy.Credentials = new NetworkCredential("user", "password", "domain");

and voila!

Probably the machine or web.config in prod has the settings in the configuration; you probably won't need the proxy tag.

<system.net>
    <defaultProxy useDefaultCredentials="true" >
        <proxy usesystemdefault="False"
               proxyaddress="http://<ProxyLocation>:<port>"
               bypassonlocal="True"
               autoDetect="False" />
    </defaultProxy>
</system.net>

HttpWebRequest webRequest = WebRequest.Create(uirTradeStream) as HttpWebRequest;

webRequest.Proxy = WebRequest.DefaultWebProxy;

webRequest.Credentials = new NetworkCredential("user", "password");

webRequest.Proxy.Credentials = new NetworkCredential("user", "password");

It is successful.

I had a similar proxy related problem. In my case it was enough to add:

webRequest.Proxy.Credentials = new NetworkCredential("user", "password", "domain");

Thought of writing this answer as nothing worked from above & you don't want to specify proxy location.

If you're using httpClient then consider this.

HttpClientHandler handler = new HttpClientHandler();

IWebProxy proxy = WebRequest.GetSystemWebProxy();
proxy.Credentials = CredentialCache.DefaultCredentials;
handler.Proxy = proxy;

var client = new HttpClient(handler);
// your next steps...

And if you're using HttpWebRequest:

HttpWebRequest request = (HttpWebRequest)WebRequest.Create(uri + _endpoint);

IWebProxy proxy = WebRequest.GetSystemWebProxy();
proxy.Credentials = CredentialCache.DefaultCredentials;
request.Proxy = proxy;

Kind referencce: https://medium.com/@siriphonnot/the-remote-server-returned-an-error-407-proxy-authentication-required-86ae489e401b