iOS requires apps to show a custom explanation string alongside every permission request — camera, microphone, contacts, and so on — and that string has to clearly and honestly explain what the permission is used for, matching the app's actual behavior.
Frequently caused by a generic or missing purpose string, like "App needs your location," that doesn't explain what feature actually needs it.
"Your app requests access to a protected resource, but the accompanying purpose string does not adequately explain how the data will be used, per guideline 5.1.1."