try this if it works for you, I haven't tried this so not sure that it will work
var remoteAddress = new EndpointAddress(Settings.EndpointAddress);
ProxyClient = new CoreServiceClient(basicHttpBinding, remoteAddress);
ProxyClient.ClientCredentials.Windows.AllowNtlm = true;
ProxyClient.ClientCredentials.Windows.ClientCredential = System.Net.CredentialCache.DefaultNetworkCredentials;
ProxyClient.ClientCredentials.Windows.AllowedImpersonationLevel = System.Security.Principal.TokenImpersonationLevel.Impersonation;