By default, SonarQube forces user authentication. You can disable forced user authentication, and allow anonymous users to browse projects and run analyses in your instance. To do this, log in as a system administrator, go to Administration > Configuration > General Settings > Security, and disable the Force user authentication property.
Disabling the Force user authentication can expose your SonarQube instance to security risks. We strongly recommend forcing user authentication on production instances or carefully configuring the security (user permissions, project visibility, etc.) on your instance.