故障异常windows phone连接到WCF WP8

我创建了一个WCF，然后创建了一个WP8应用程序并添加了服务引用。错误是System.ServiceModel.ni.dll中发生的“System.ServiceModel.FaultException”类型的异常，但未在用户代码中处理

如果有人能给我一些提示，因为我已经在谷歌上搜索过了，没有发现任何相同的东西

这里出现了错误

public void EndAddUser(System.IAsyncResult result) 
{
    object[] _args = new object[0];
    base.EndInvoke("AddUser", _args, result);
}

我的主要课程：

public partial class MainPage : PhoneApplicationPage
{
    private Service1Client _serviceClient;
    // Constructor
    public MainPage()
    {
        InitializeComponent();
        _serviceClient = new Service1Client();
        _serviceClient.LoginUserCompleted += new     

    }

    private void loginBtn_Click(object sender, RoutedEventArgs e)
    {
        _serviceClient.LoginUserAsync(userNameTxtBox.Text, passwordTxtBox.Text);

    }

    private void newAccountBtn_Click(object sender, RoutedEventArgs e)
    {
        this.NavigationService.Navigate(new Uri("/AddAccount.xaml", UriKind.Relative));
    }

    private void _serviceClient_LoginUserCompleted(object senter,         
    LoginUserCompletedEventArgs e)
    {
        if (e.Error == null && e.Result != null)
        {

            MessageBox.Show("Welcome " + e.Result + "!");
        }
        else
        {
            MessageBox.Show("Could not log in. Please check user name/password and try
          again.");                  
        }
    }
}



public partial class AddAccount : PhoneApplicationPage
{
    private Service1Client _serviceClient;

    public AddAccount()
    {
        InitializeComponent();
        _serviceClient = new Service1Client();
        _serviceClient.AddUserCompleted += new EventHandler<AsyncCompletedEventArgs>
        (_serviceClient_AddUserCompleted);
    }

    private void addAccountBtn_Click(object sender, RoutedEventArgs e)
    {
        _serviceClient.AddUserAsync(fullnameTxtBox.Text, userNameTxtBox.Text,   
       passwordTxtBox.Text);
    }

    void _serviceClient_AddUserCompleted(object sender, AsyncCompletedEventArgs e)
    {
        if (e.Error == null)
        {
            MessageBox.Show("User account created. Please login");
            this.NavigationService.GoBack();
        }
        else
        {
            MessageBox.Show("User account could not be added, Please try again");
        }
    }
}

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1.捕捉异常2。在异常3上调用.ToString。复制调用结果的整个文本，然后单击4。请回答您的问题并在此处添加此信息。它可能包含了解决问题所需的所有信息。请检查您是否有正确的url，以及服务是否正常工作。要进行此测试，您可以使用VisualStudio所在的同一文件夹中的WCFTestClient.exe（devenv.exe）