By default, access to Dynamics 365 Portal site(e.g. https://XXXXX.microsoftcrmportals.com), Home screen is displayed. On Home screen, click [Sign in], the customer acknowldeges the default behavior of displaying sign in screen.
When accessing Dynamics 365 Portal, need to access to sign in screen without going through home screen. However, by default, cannot directly access to sign in screen.
It would be more reliable service if such a capability is added on Dynamics 365 Portal.
This is already possible today, you have to make your home page as authenticated and that will redirect you automatically to either your signin page or to your identity provider (if there is a default configrued)