auth.cannot_unlink_only_auth
Unlinking Google would remove the user's only remaining authentication method.
auth.cannot_unlink_only_auth is returned by POST /v1/auth/google/unlink (or DELETE /v1/auth/google/link) when removing the Google link would leave the account with no remaining authentication factor. The platform enforces that every account has at least one sign-in method.
The user is trying to unlink their Google account but has not set up any other sign-in method (e.g., magic-link via a verified email address is not configured).
Add a magic-link-compatible email or another auth method to the account before unlinking Google.
{
"error": {
"code": "auth.cannot_unlink_only_auth",
"message": "cannot remove the only remaining authentication method",
"request_id": "req_01900000abc"
}
}