The HTTP request is unauthorized with client authentication scheme 'Ntlm' while calling SAP PI web service

Question

I am currently creating a .net C# service which uses webservice invoking to send information from CRM 2011 to SAP.

The credentials are said as following:

((BasicHttpBinding)defaultBinding).Security.Mode = BasicHttpSecurityMode.TransportCredentialOnly;
((BasicHttpBinding)defaultBinding).Security.Transport.ClientCredentialType = HttpClientCredentialType.Basic; //.Ntlm;

PropertyInfo piClientCreds = type.GetProperty("ClientCredentials");
ClientCredentials creds = (ClientCredentials)piClientCreds.GetValue(obj, null);
PropertyInfo piWindowsCreds = creds.GetType().GetProperty("Windows");
WindowsClientCredential windowsCreds = (WindowsClientCredential)piWindowsCreds.GetValue(creds, null);
PropertyInfo piAllowNtlm = windowsCreds.GetType().GetProperty("AllowNtlm");
piAllowNtlm.SetValue(windowsCreds, true, null);
PropertyInfo piCredentials = windowsCreds.GetType().GetProperty("ClientCredential");
piCredentials.SetValue(windowsCreds, credentials, null);
PropertyInfo piImpersonation = windowsCreds.GetType().GetProperty("AllowedImpersonationLevel");
piImpersonation.SetValue(windowsCreds, System.Security.Principal.TokenImpersonationLevel.Impersonation, null);

The error I get is:

{System.ServiceModel.Security.MessageSecurityException: The HTTP request is unauthorized with client authentication scheme 'Ntlm'. The authentication header received from the server was 'Basic realm="Upload Protected Area"'. ---> System.Net.WebException: The remote server returned an error: (401) Unauthorized. at System.Net.HttpWebRequest.GetResponse() at System.ServiceModel.Channels.HttpChannelFactory.HttpRequestChannel.HttpChannelRequest.WaitForReply(TimeSpan timeout) --- End of inner exception stack trace ---

Any help in resolving this and if possible making it dynamic is much appreciated.

Thank you in advanced.

Answer 1

The problem is quite obvious. The server expects the your client to use Basic authentication while your client attempts to authenticate using NTLM. Try authenticating using UserNamePasswordClientCredential . You should do this only over a secure transport such as HTTPS.