Cannot add any assets to CC Libraries sometimes. Plus button greyed out.
I have occasionally faced this issue where I cannot add any assets to my CC libraries panel in either Illustrator, Photoshop, or InDesign. I can't find any forums that point to this exactly and have tried varies things like closing all Adobe programs, signing in and out of Creative Cloud, refreshing all CC process and such to no avail.

As you can see, the plus 'Add Content' button is greyed out regardless of any artwork being selected. Even when a shape is selected and I click any of these colours in my library, nothing happens.
