I used GData API to pull in Calender info. It works fine if I use 1.6. But the same code, if I change to Android 2.0 & up, it would throw AuthenticationException. Below is my code for ur ref: CalendarService myService = new CalendarService("My Application"); myService.setUserCredentials(args[0],args[1]); // Set up the URL and the object that will handle the connection: URL feedUrl = new URL("http://www.google.com/calendar/feeds/"+args[0]+"/private/full"); args[0] & args[1] are the credentials. AuthenticationException will be thrown when calling myService.setUserCredentials(). Anybody has any clue?