Hey @goldytech,
Have you registered the correct authorized redirect URI in Google? It should be https://<YOUR_AUTH0_DOMAIN>/login/callback.
See this doc for more info.
For other possible reasons, please take a look at the following:
- https://community.auth0.com/t/mismatched-uri-using-github-as-a-social-provider/2981
- Try button for any SSO Connection has trouble with Redirect URI
I hope this helps.