Unable to Programatically Call Gateway OData Services from AppBuilder

Hello Experts,

I'm facing a problem while trying to read OData service programmatically. for eg: OData.read() or odataModel.read() functions.

IDE being used is SAP AppBuilder 1.0.

There is no problem, if the service is being called in the SuperList control.

When it is being read from code, the following error is returned in the response.

{"message":"HTTP request failed","request":{"requestUri":"http://abcd.xyz.com:8055/sap/opu/odata/sap/Z_ABC_SRV/PurchaseOrderSet('4500000042')","headers":{"Accept-Language":"en-us","Accept":"application/json","MaxDataServiceVersion":"2.0","DataServiceVersion":"2.0","proxy":"true"},"async":true,"user":"username","password":"passwd","withCredentials":false,"recognizeDates":false,"callbackParameterName":"$callback","formatQueryString":"$format=json","enableJsonpCallback":false,"inferJsonLightFeedAsObject":false,"method":"GET"},

"response":{"requestUri":"http://abcd.xyz.com:8055/sap/opu/odata/sap/Z_ABC_SRV/PurchaseOrderSet('4500000042')","statusCode":0,"statusText":"","headers":[],"body":""}}

Source code is as follows:

var ServiceURL = "http://abcd.xyz.com:8055/sap/opu/odata/sap/Z_ABC_SRV/";

var odataModel = new sap.ui.model.odata.ODataModel(ServiceURL,true,"username","passwd");

sap.ui.getCore().setModel(odataModel);

odataModel.read("PurchaseOrderSet('"+this.selectedPo+"')",

                        null,

                        null,

                        true,

                        function(oData, oResponse){

                            alert(JSON.stringify(oResponse));

                        },

                        function(oError){

                                alert(JSON.stringify(oError));

                        }

            );

Regards,

Anish