Your session has timed out.

[tmcdonald]

I can replicate this by using the short hostname in the landing page definition.
Once changed to the FQDN the problem disappears.
In fact the issue is that the hostname used in the landing page needs to be an exact match of the name defined in /Admin/Manage System Config/Program URL.
If you use FQDN in one setting, use FQDN in all settings...

This thread is quite old and the issue has been fixed in recent versions. If you're having this issue first try updating, otherwise open a new thread and we'll help out there. Closing this thread.