If you are redirecting users based on their Active Directory group, Group Redirect requires access to an Active Directory account – this is how the web part determines who is redirected, and who is not.
NOTE: If you are redirecting users based solely on their SharePoint group, you do not need to provide any Active Directory information. However, if you want any of your rules criteria (including AND/OR rules) to include Active Directory groups, you must provide login information.
You can see the entire tool pane that needs to be configured; we have broken down the sections of the tool pane so you can quickly locate the information that you need to configure the first time or subsequent times.