WCF-ASP.NET Connection Error

Question

Hello, i have a problem with my WCF connection to my asp.net application.
I know that it is pretty much the same as a connection to a WPF app but somehow it wont start.

here my example code

WCF

// NOTE: You can use the "Rename" command on the "Refactor" menu to change the interface name "IService1" in both code and config file together.
[ServiceContract]
public interface IService1
{
[OperationContract]
IEnumerable GetStudentFromClass(String className);

    [OperationContract]  
    StudentItem GetStudentByMatNr(String matNr);  

    [OperationContract]  
    IEnumerable GetStudentsByName(String name);  

    [OperationContract]  
    IEnumerable GetAll();  

    // TODO: Add your service operations here  
}  

[DataContract]  
public class StudentItem  
{  
    [DataMember]  
    public String MatrikelNr { get; set; }  
    [DataMember]  
    public String Vorname { get; set; }  
    [DataMember]  
    public String Nachname { get; set; }  
    [DataMember]  
    public String Strasse { get; set; }  
    [DataMember]  
    public String Ort { get; set; }  
    [DataMember]  
    public String Telefonnr { get; set; }  
    [DataMember]  
    public String Email { get; set; }  
    [DataMember]  
    public String Klasse { get; set; }  
    [DataMember]  
    public DateTime? Geburtsdatum { get; set; }  
    [DataMember]  
    public int? Plz { get; set; }  

    public StudentItem(Student student)  
    {  
        this.MatrikelNr = student.MatrikelNr;  
        this.Vorname = student.Vorname;  
        this.Nachname = student.Nachname;  
        this.Strasse = student.Strasse;  
        this.Ort = student.Ort;  
        this.Telefonnr = student.TelefonNr;  
        this.Email = student.EMail;  
        this.Klasse = student.Klasse;  
        this.Geburtsdatum = student.Geburtsdatum;  
        this.Plz = student.PLZ;  
    }  

    public StudentItem()  
    {  

    }  
}

WCF SVC
public class Service1 : IService1
{
StudentItemEntities studentItemEntities = new StudentItemEntities();

    public IEnumerable GetAll()  
    {  
        var query = from Student  
                    in studentItemEntities.Student  
                    select new StudentItem  
                    {  
                        MatrikelNr = Student.MatrikelNr,  
                        Vorname = Student.Vorname,  
                        Nachname = Student.Nachname,  
                        Strasse = Student.Strasse,  
                        Ort = Student.Ort,  
                        Telefonnr = Student.TelefonNr,  
                        Email = Student.EMail,  
                        Klasse = Student.Klasse,  
                        Geburtsdatum = Student.Geburtsdatum,  
                        Plz = Student.PLZ  
                    };  

        return query;  
    }  

    public StudentItem GetStudentByMatNr(string matNr)  
    {  
        var query = from Student  
        in studentItemEntities.Student  
                    where Student.MatrikelNr.Equals(matNr)  
                    select new StudentItem  
                    {  
                        MatrikelNr = Student.MatrikelNr,  
                        Vorname = Student.Vorname,  
                        Nachname = Student.Nachname,  
                        Strasse = Student.Strasse,  
                        Ort = Student.Ort,  
                        Telefonnr = Student.TelefonNr,  
                        Email = Student.EMail,  
                        Klasse = Student.Klasse,  
                        Geburtsdatum = Student.Geburtsdatum,  
                        Plz = Student.PLZ  
                    };  
        StudentItem studentItem = (StudentItem)query;  
        return studentItem;  
    }  

    public IEnumerable GetStudentFromClass(string className)  
    {  
        var query = from Student  
                    in studentItemEntities.Student  
                    where Student.Klasse.Equals(className)  
                    select new StudentItem  
                    {  
                        MatrikelNr = Student.MatrikelNr,  
                        Vorname = Student.Vorname,  
                        Nachname = Student.Nachname,  
                        Strasse = Student.Strasse,  
                        Ort = Student.Ort,  
                        Telefonnr = Student.TelefonNr,  
                        Email = Student.EMail,  
                        Klasse = Student.Klasse,  
                        Geburtsdatum = Student.Geburtsdatum,  
                        Plz = Student.PLZ  
                    };  

        return query;  
    }  

    public IEnumerable GetStudentsByName(string name)  
    {  
        var query = from Student  
        in studentItemEntities.Student  
                    where (Student.Vorname.Equals(name) || Student.Nachname.Equals(name))  
                    select new StudentItem  
                    {  
                        MatrikelNr = Student.MatrikelNr,  
                        Vorname = Student.Vorname,  
                        Nachname = Student.Nachname,  
                        Strasse = Student.Strasse,  
                        Ort = Student.Ort,  
                        Telefonnr = Student.TelefonNr,  
                        Email = Student.EMail,  
                        Klasse = Student.Klasse,  
                        Geburtsdatum = Student.Geburtsdatum,  
                        Plz = Student.PLZ  
                    };  

        return query;  
    }  
}

ASP.NET CS
public partial class WebForm1 : System.Web.UI.Page
{
private ServiceReference1.IService1 client = new ServiceReference1.Service1Client();

    protected void Page_Load(object sender, EventArgs e)  
    {  
        GridView1.DataSource = client.GetAll();  
        GridView1.DataBind();  
    }  
}

<%@ Page Language="C#" AutoEventWireup="true" CodeBehind="WebForm1.aspx.cs" Inherits="WebApplication2.WebForm1" %>

WPF

xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
xmlns:local="clr-namespace:WpfApp1"
mc:Ignorable="d"
Title="MainWindow" Height="450" Width="800">