Comment 18 for bug 451336

Both should work. The one you pasted there won't work on production right now because of a known bug. There's a fix already on staging which you can see here:

https://login.staging.ubuntu.com/+logout?return_to=https%3A%2F%2Flandscape.canonical.com%2F

It's expected on production in the next few days, subject to sysadmin availability.