Response coming null

var options = {
    url: 'http://184.106.159.143:8080/FirstGroupRailApps/services/RailAppsCAWS/getDestinationStationDashboard',
    method: "POST",
    params: {
        param1:"AAP",

    },
    callback: function(options, success, response){
        if (success) {
        alert("Hi");
        console.log(response);
        console.log(response.responseXML);
            var store = new Ext.data.XmlStore({
                storeId: 'getDestinationStationDashboardResponse',//what is storeID?
                autoLoad: true,
                autoDestroy: true,
                data: response.responseXML,
                //record: 'root',
                //idPath: 'ID',//ID path
                //fields: ...,
                //sortInfo: {
                  //  field: 'ID',
                   // direction: 'DESC'
                //}
            });
        } else {
        alert("Bye");
            for (var prop in response) {
                air.trace(prop + " = " + response[prop]);
            }
        }
    }
};
Ext.Ajax.request( options );