Sonata Admin Two-Steps Google Authentication

Question

I followed this guide to setup the two-steps authentication:

https://sonata-project.org/bundles/user/3-x/doc/reference/two_step_validation.html

Unfortunately the documentation is very short and I couldn't make it work. These are steps I followed:

1. Configured my config.yml like this:

   google_authenticator: enabled: true server: my-admin-url.local # Is this my site URL?

2. php app/console sonata:user:two-step-verification admin to populate the field?

3. After the login I get this screen. What should I do?