So:
- a user logs into Google, they are now logged into Google
- They then go to your site, and login via a social login, they are now logged into your site, and they are logged into google
- The user logs out of your site, they’re now logged out of your site, but still logged into google
The problem being that you want logging out of your site to also log them out of google? This is not possible.
Google sessions, Google cookies, are all Google things, that you have zero control over, by design. You’re not supposed to be able to do what you’re trying to do, and if you could, it would be considered a major bug that must be fixed immediately.
All you can do, is tell the user to log out of Google.
Keep in mind too, that the user will not be expecting to be logged out of Google, that’s not how SSO works with Social Logins. There’s no reason for them to log out of Google, and having it happen unexpectedly would be annoying.
If you really wanted to do this though, you’d need to run your code on Google owned domains, the only way to do that is to work at Google