Redirecting logout using custom URLs does not log users out of Business Space.
Redirecting logout does not work, and cookies are not being deleted.
Cookies are not being deleted.
Diagnosing the problem
Check if cookies are being deleted.
Resolving the problem
If cookies are not being deleted, then delete the generation of cookies.
For example, if LtpaToken2 is not being deleted, then in the admin console, go to Global Security -> single sign-on (SSO), and blank out the domain name.