When an administrator is closing projects it is best to do this using the global 'Workspaces and Projects' tools and configuration menu. If using the project picker menu tools, the user will be kicked out of the application.
(Note: these options are available only to Project, Workspace, and Subscription Administrators)
When anyone is set to a project that gets closed, those users are logged out of Rally.
The Administrator should set themselves to a project that will remain open. Then proceed to close their project(s) using the Setup > Workspaces & Projects menu.