C# 神秘的WCF身份验证错误

我有一个ASP.net网站设置，我正试图通过它调用WCF服务。服务返回以下（无意义的）错误：

HTTP请求未经客户端身份验证方案“Ntlm”授权。从服务器接收的身份验证标头为“NTLM”

WCF客户端和服务器由代码生成，具有以下绑定定义：

客户端基本绑定

var binding = new BasicHttpBinding(BasicHttpSecurityMode.TransportCredentialOnly);
binding.Security.Transport.ClientCredentialType = HttpClientCredentialType.Ntlm;

basicHttpBinding.Security.Mode = BasicHttpSecurityMode.TransportCredentialOnly;
basicHttpBinding.Security.Transport.ClientCredentialType = HttpClientCredentialType.Ntlm;

Server BasicHttpBinding

var binding = new BasicHttpBinding(BasicHttpSecurityMode.TransportCredentialOnly);
binding.Security.Transport.ClientCredentialType = HttpClientCredentialType.Ntlm;

basicHttpBinding.Security.Mode = BasicHttpSecurityMode.TransportCredentialOnly;
basicHttpBinding.Security.Transport.ClientCredentialType = HttpClientCredentialType.Ntlm;

IIS配置
IIS仅配置为NTLM身份验证，如下所示：

Windows身份验证提供程序的配置如下：

同样的配置在另外两个环境中工作。这两者之间的唯一区别是工作服务器运行在Windows 2008 R2上，而非工作环境运行在Windows 2012上

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