Issue
Without signing into the instance, when opening the Service Portal home page (https://<InstanceName>.service-now.com/sp), the sign-in page configured in the portal record should display. Instead, the home page displays.
Release
Any supported release
Cause
The home (index) page is set to public as shown in the following image. This causes the system to bypass the sign-in page and displays the home page instead.
Resolution
Do not set the home page (index page) to public. Unchecking this box displays the correct sign-in page.