I can't get connected to my internal ArcGIS Server from the Android ArcGis App. I can connect to arcgismobile.esri.com/arcgis/mobile. Take note that I just set up the ArcGIS server 10.1 beta. Published a simple feature service that I can access from ArcMap. I remembered to include the MobileService and can see it on the server services url. I get the feeling that it is a server security issue but am not sure. I can also ping the server ip address from my android without issue.