if (e.getCode() == 404) {
// event was deleted by the user.
//e.printStackTrace();
Activity activity = getState().get("activity",Activity.class);
Attendee attendee = activity.withConstraints().withAttendee(agent);
attendee.setResponseStatus(RESPONSE_STATUS.declined);
getState().put("activity", activity);
clearAttendee(agent); // TODO: seems not to work
} else {
e.printStackTrace(); // TODO: remove print stacktrace