I was working with the Esri Public Information app on my dev machine. I could not get the Instagram Layer to work as I kept getting an error that read (Instagram::400 - Instagram: The access_token provided is invalid.) on the Chrome dev tools.
I downloaded the app on GitHub (Link Below) and got it running with a web map I created on ArcGIS Online. I registered my app with Instagram and got a new Client ID and entered in in the "instagram_key" section of the "default.js" file. Still no luck.
I will continue looking into this and update if I find anything.