I use Odoo 10.
I set it up Oauth2 with Google.
When you add a user, you receive the invitation and you can enter with your google account. When you log out and try to log in again sends you this message:
You do not have access to this database or your invitation has expired. Please ask for an invitation and be sure to follow the link in your invitation email.
I send the invitation again and enter but if it happens the same happens