About this question
How to enable and configure topics for objects in lightning? FYI. I don't see topics for objects in the quick find box. I have built a community using Napili Template in lightning but I can't add articles under the navigation menu and assign them using data categories. I get this error when I try to add articles : Assigning the topics you've selected isn't allowed. A Salesforce admin must enable topics for objects for the article type(s).