Issue
You are trying to access an URL like the following:
and you are taken to a ServiceNow portal login page that you are not familiar with instead of being taken to the record you wish to access.
In fact going via yourinstance.service-now.com/kb gives the same result
Your $sp page is marked as public in the sys_public.list of the instance
Release
All
Cause
Most probably you are missing a login page from the KB portal.
https:/yourinstance.service-now.com/nav_to.do?uri=sp_portal.do?sys_id=45d6680fdb52220099f93691f0b8f5ad (replace yourinstance with the name of your instance)
Resolution
To overcome this, as the landing page in the login section of the KB portal, as in the below screenshot.
