Getting JSON to properly work

Hello,
I am trying to use the JSON Content Importer to show AL-ANON meetings nationwide however the API link I feed does not work? There is barely any documentation on this plugin?

I have altered the gutenburg example that comes with this plugin and it does show the data I need however I need that data to look like this page AL-ANON MEETING FINDER

Any help would be much appreciated. I am trying to use the data from this repository online-meeting-finder

When I create a page and use the JSON content importer and enter the URL I need to display it tells me this error;

"error": {
    "code": 401,
    "message": "Request had invalid authentication credentials. Expected OAuth 2 access token, login cookie or other valid authentication credential. See https://developers.google.com/identity/sign-in/web/devconsole-project.",
    "status": "UNAUTHENTICATED"
  }
}

Any possible fixes to this?

The page I need help with: [log in to see the link]