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

[dannystommen]

Hi all,

I have the following existing code (already in production for a few months)

using (System.Net.WebClient client = new System.Net.WebClient()) {
client.Credentials = new System.Net.NetworkCredential("user", "pass", "domain");

XmlDocument xmlDoc = new XmlDocument();
xmlDoc.Load(client.OpenRead("http://url.com/doc.xml"));
...
}

Since yesterday, I recieve the following exception on client.OpenRead: Webclient: The remote server returned an error: (407) Proxy Authentication Required.

Now I changed the code to

using (System.Net.WebClient client = new System.Net.WebClient()) {
client.Credentials = new System.Net.NetworkCredential("user", "pass", "domain");
client.Proxy = new System.Net.WebProxy() {
Credentials = new System.Net.NetworkCredential("user", "pass", "domain")
};
}

Now it is working again, but this would mean that everyone here needs to reinstall the application (it's a winform app).

The folder where the XML file is located, is secured with Windows Authentication. Even if I enable Anonymous Authentication in IIS, I get the same exception.

Is there any way to prevent this error from happening without the code change, so that the users do not need to reinstall the app?

[dannystommen]

Really strange, the exception disappeared... The network administrator here is not aware of any changes made that possibily could have caused this error.

Anyone here an idea?