After logging in as an administrator, you may see the following error:
The requested page was not found due to the following reasons. No Active Page was found for the url you requested.
This occurs because the AdminHomePage is in a Security Category that you are not able to view. A Site Administrator can change the security category of this page (to General) so that you are able to view it.
Despite this error you can still navigate to any other available tab (such as Constituent360) without having to view the content of that page.