C＃模仿总是返回false

Question

我尝试使用LogonUser方法连接到另一台计算机以保存文件。这是我的代码：

public class ImpersonationHelper
{
    [DllImport("advapi32.dll", SetLastError = true, CharSet = CharSet.Unicode)]
    public static extern bool LogonUser(String lpszUsername, String lpszDomain, String lpszPassword, int dwLogonType, int dwLogonProvider, ref IntPtr phToken);

    enum LogonType
    {
        Interactive = 2,
        Network = 3,
        Batch = 4,
        Service = 5,
        Unlock = 7,
        NetworkClearText = 8,
        NewCredentials = 9
    }

    enum LogonProvider
    {
        Default = 0,
        WinNT35 = 1,
        WinNT40 = 2,
        WinNT50 = 3
    }

    public IntPtr Login(string username,string password)
    {
        // machineIp
        string domain = "XXX.XX.XX.XX";
        int logonType = (int)LogonType.Network;
        int logonProvider = (int)LogonProvider.WinNT50;
        IntPtr tokenHandle = IntPtr.Zero;
        bool returnValue = LogonUser(username, domain, password, logonType, logonProvider, ref tokenHandle);
        if (!returnValue)
        {
            int nErrorCode = Marshal.GetLastWin32Error();
            throw new System.ComponentModel.Win32Exception(nErrorCode);
        }
        return tokenHandle;
    }
}

LogonUser的返回值始终为false，Marshal.GetLastWin32Error（）的值有时为0（表示＆＃34;操作成功完成＆＃34;）然后是1326（表示＆＃34;用户名或密码为不正确＆＃34）。我的错误是什么？