GoogleCalendarへのインポートが動かない

gistfile1.js

function myFunction() {

  var auth_user = Session.getActiveUser().getEmail();
  var oauth = UrlFetchApp.addOAuthService('calendar');
  oauth.setConsumerKey("XXXXXXXXXXXXXXXXXXX");
  oauth.setConsumerSecret("XXXXXXXXXXXXXXXXXXXXXXX");
  oauth.setRequestTokenUrl("https://www.google.com/accounts/OAuthGetRequestToken?scope=https%3A%2F%2Fwww.googleapis.com%2Fauth%2Fcalendar");
  oauth.setAuthorizationUrl("https://www.google.com/accounts/OAuthAuthorizeToken");
  oauth.setAccessTokenUrl("https://www.google.com/accounts/OAuthGetAccessToken");
  
  var payload = {
    'summary': 'Appointment',
    'start': {
      'dateTime': '2012-06-09T10:00:00.000-07:00'
    },
    'end': {
      'dateTime': '2012-06-09T10:25:00.000-07:00'
    },
    'iCalUID': 'originalUID',
    'attenders': [
      {
        'email': 'XXXXXXXXXXXXXXXXXXXXXXXXXXXXXX',
      }
    ],
    'reminders':{
      'overrides': [
        {
          'method': 'email',
          'minutes': '10'
        }
      ]
    }
  };
  
  var options = {
    "method" : "post",
    "oAuthServiceName" : 'calendar',
    "oAuthUseToken" : "if_available",
    "payload": payload,
    "contentType":  "application/json"
  };

  var url = 'https://www.googleapis.com/calendar/v3/calendars/XXXXXXXXXXXXXXXXXXXXXXXX/events/import';
  var res = UrlFetchApp.fetch(url, options);
  var test = res.getContentText("UTF-8");
  Logger.log(test);
  
}