I think, you will need something, which switches to your context, for example the xrouting-plugin
Also, make sure your User Group has a Context Access ACL entry giving access to the new context with a Policy of "Administrator". If that works, you can use a more restrictive Policy later.
When you preview a document from the Manager, your status is unusual. You are not logged in in the front end, though you will have 'view_unpublished' permission. IIRC, the rest of the permissions are those of the (anonymous) user. Permission-wise, you won't see the front end as a real visitor would.