Mobile app stucks at loading dots

Hello.

I am using v2.3.1 with phonegap and remote build. When I set the store proxy at jsonp, the app works perfectly on pc browser but on mobile the app stucks at loading blue screen with dots.

Any help highly appreciated!

Code:

Ext.define('MyApp.store.Promos', {    extend: 'Ext.data.Store',


    requires: [
        'MyApp.model.Promo',
        'Ext.data.proxy.JsonP'
    ],


    config: {
        autoLoad: false,
        //autoSync: true,
        pageSize: 100,
        model: 'MyApp.model.Promo',
        storeId: 'Promos',
        proxy: {
            type: 'jsonp',
            url: MyApp.app.rpcProxy,
            useDefaultXhrHeader: false,
            reader: {
                type: 'json',
                rootProperty: 'promos'
            }
        }
    }
});