Administrators can change where users land in Universe from the general settings. By default users land in My Stream.
In here admins have 2 options, either my stream or primary page. The My stream option is quite clear, but the Primary page does have some options inside it.
If users land in the Primary page and do not have access to the primary page, they will be routed to a secondary page (in whatever order the secondary pages are received from the server). If user does not have access to the primary page or to any secondary page, they will be routed to my stream.
The order is therefore the following: