calendar from apps script : every time authorized required. Only work with primary calendar

Question

In a spreadsheet, I have a app script for count hours in a google calendar and the output is copied in the spreadsheet.

A few days ago, anything worked fine.

but

Answer 1

finally I changed the access to calendar API to CalendarApp service with .getEvents

var cal = CalendarApp.getCalendarById(cal_id);
var this_year = new Date(2013,0,1);
var now = new Date()
var events = cal.getEvents(this_year, now, {search: event_name});