This.auth.login('google') not working

Hi, I am trying use social login on an Ionic 2 app I am working on.
I am using the instructions found here

I managed to get Facebook login working successful (with similar instructions), but Google is not working.

It does open the google log in screen, I log in to Google, and after google is successfully login I get the following on the screen:
> {
> “error”: {
> “type”: “InternalServerError”,
> “message”: “500: Internal Server Error”,
> “link”: null
> },
> “meta”: {
> “request_id”: “-”,
> “status”: 500,
> “version”: “2.0.0-beta.0”
> }
> }

I am sure there must be some setting I have missed; a client Id, or secret, or a CORS setting on Google.
I have gone through everything a few times, and I can’t find where the problem is.

Does anyone know what the most likely problem is, based on the response?