Your Global Redirect can be found and set in SET UP > SETTINGS > TRACKING SETTINGS
By default, the Global Redirect is set to a CAKE Basic 404 page.
The 404 can be optionally replaced with a URL where the customer is redirected on invalid/inactive links and after all Upsell and Redirect paths have been exhausted when no Thank You Link is present.
The Global Redirect should NEVER be a CAKE Basic Unique Link.
You can see our entire redirect strategy here.
You can also see dispositions on why clicks redirected in your click report from the Advertisers Stats subtab.