I'm including the official Facebook Page Plugin (not my own app) on my website. The plugin shows as a widget with a "share" button at the top. On Chrome, Firefox, iOS 8.4 Safari, clicking that goes to a share page. But on iOS 9.2 Safari (on an iPhone 6), clicking that share button shows a page with the error:
App not setup. This app is still in development mode, and you don't have access to it. Switch to a registered test user or ask an app admin for permissions.
To eliminate any other code, I made a flat HTML page that has nothing but the Facebook code and it still does this.
What could cause this?