404 Not Found

I’m trying to set up a grouped calendars and starting with one but keep getting the message below:

While trying to retrieve events, Google returned an error:{
 "error": {
  "errors": [
   {
    "domain": "global",
    "reason": "notFound",
    "message": "Not Found"
   }
  ],
  "code": 404,
  "message": "Not Found"
 }
}
Please ensure that both your Google Calendar ID and API Key are valid and that the Google Calendar you want to display is public.

I’ve verified the API Key and that the Google Calendar is public (https://calendar.google.com/calendar/embed?src=chair%40readingscouting.org&ctz=America%2FNew_York)
The API Key is not restricted.

Thanks!

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