Android : Android Studio Webservice call "HTTP request failed, HTTP status: 401" Unauthorized

i try to connect my Android application to a Webservice. I wrote a new class and defined some Variables:

I´ve got the Async Class to use the Network

class GetValueTask extends AsyncTask<ApiConnector,Long,String> {
@Override
protected String doInBackground(ApiConnector... params) {
    //wird im Background Thread ausgeführt
    return  params[0].getValue();

}

@Override
protected void onPostExecute(String s) {
    //wird im Mainthread ausgeführt
    MainActivity.this.setText(s);
}

}

And I have a Class where i want to call the Webservice

public class ApiConnector {

private static final String SOAP_ACTION ="urn:microsoft-dynamics-schemas/codeunit/AddService:Add";
private static final String METHOD_NAME ="Add";
private static final String NAMESPACE ="urn:microsoft-dynamics-schemas/codeunit/AddService";
private static final String URL ="http://192.168.0.154:9047/DynamicsNAV80/WS/CRONUS%20AG/Codeunit/AddService";
private static final String USERNAME="B.Denger";
private static final String PASSWORD ="TestPW123!";



public String getValue() {

    SoapObject request = new SoapObject(NAMESPACE,METHOD_NAME);
    request.addProperty("no","10");

    PropertyInfo unamePI = new PropertyInfo();
    PropertyInfo passPI = new PropertyInfo();
    // Set Username
    unamePI.setName("username");
    // Set Value
    unamePI.setValue(USERNAME);
    // Set dataType
    unamePI.setType(String.class);
    // Add the property to request object
    request.addProperty(unamePI);
    //Set Password
    passPI.setName("password");
    //Set dataType
    passPI.setValue(PASSWORD);
    //Set dataType
    passPI.setType(String.class);
    //Add the property to request object
    request.addProperty(passPI);

    SoapSerializationEnvelope soapEnvelope = new SoapSerializationEnvelope(
            SoapEnvelope.VER11);

    soapEnvelope.setOutputSoapObject(request);

    HttpTransportSE aht= new HttpTransportSE(URL);

    try {
        aht.call(SOAP_ACTION, soapEnvelope);
        SoapPrimitive resultString = (SoapPrimitive) soapEnvelope.getResponse();
        return resultString.toString();
    }catch(Exception e ) {
        e.printStackTrace();
        return "Fail at Call";
    }
}

}

I have set the using-permission in the Manifest file

<uses-permission android:name="android.permission.INTERNET"/>

in my MainActivity do i execute the AsynkTask with a Button

 btn.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            GetValueTask getValueTask = new GetValueTask();
            getValueTask.execute(new ApiConnector());
        }
    });

after execution i get following Logcat entry: W/System.err﹕ org.ksoap2.transport.HttpResponseException: HTTP request failed, HTTP status: 401

i googled a whole Day for it, but i did not solved the problem yet. is there anybody who could help me, or could give me a hint where i have to search?