I’m using a Shield with a portable hard drive. I created a network drive and I can see it and folders when trying to add content to a new library. When I click on the folder the content is showing but grayed out?
Did you already have a chance to look at this support article on how to prepare/connect your storage to the SHIELD?
https://support.plex.tv/articles/220391808-media-storage-options-for-nvidia-shield/