Apart from the global settings under Admin-> Channels -> Portals-> Settings, you would also have to ensure that the folders have been given global access. Under Solutions, when you click on the category name, then the folder name, and choose edit, you would find an option to choose the visibility for this folder.
You can choose to make the folder visible to all, only to logged-in users or agents alone depending on your requirement. You can go further and make it visible to specific companies by entering their name