Hi,
I am having the same issue - we have the mbox setup, and I am trying to create an experiment for a page within our logged-in section.
I have tried the two methods you mentioned above, but neither is working; I keep getting our log-in error page, and a message saying my session has expired. It has not! Is there anything you might be able to suggest in the implementation that might be blocking this? Or is this an error on our site and the way the pages are built?
Within the "browse" mode I get things like our live chat message pop up, and I can navigate to any other page on the site, the issue is just with being able to log-in.