Google Apps Script: Unable to send emails using createEvent()

I have the following code and attendees are not able to receive emails about the event. Though the event is reflecting in their calendar.

    var options = {  
     description: description,
     location: location,
     guests: email_address,
     sendInvites: true
   }
   var event = CalendarApp.getCalendarById(calendarId).createEvent(title,
                start_datetime, end_datetime,
                options);

I have added oauthScopes to appsscript.json as well.

"oauthScopes": [
   "https://www.googleapis.com/auth/calendar",
   "https://www.google.com/calendar/feeds"
 ]

It seems like an authorization issue but not sure how to solve this.