Enterprise administrators can now choose to redirect signed-out Enterprise Managed Users to their company's single sign-on (SSO) page. This feature is available as a public beta.
By default, enterprises with Managed Users enabled are hidden, showing a
404 error page any time an enterprise resource is visited by a user that isn't already signed in to the enterprise.
If you enable this feature for your enterprise, visitors to resources in your enterprise, org, or user namespaces will immediately be presented with an SSO redirect if not already signed in to your enterprise.
This redirect helps users sign in to the correct account, rather than giving them the impression that the link they were given no longer works.
You can find this setting in the Authentication security section of your Enterprise Settings, below the single sign-on configuration sections.
Read more about this settings at "Automatic redirection for Enterprise Managed Users".