Signing in using your GitLab.com account without a pre-existing GitLab account is not allowed. Create a GitLab account first, and then connect it to your GitLab.com account

Getting the following error when trying to login using gitlab or github buttons. My expectation of those buttons is they follow SSO conventions and let me sign in to the gnome gitlab instance using my details on google, gitlab or github. However the error seems to suggest I need to create an account on the gnome instance first. This is not how SSO is supposed to work. It should sign me in and then ask me to confirm some details maybe. I shouldn’t have to create an account first, that defeats the point of SSO. I suspect gnome have not configured their SSO to operate as per the standard. If those buttons aren’t supposed to work they should be removed.

The error:
Signing in using your GitLab.com account without a pre-existing GitLab account is not allowed. Create a GitLab account first, and then connect it to your GitLab.com account.