IDFA iOS14 returns denied without displaying auth popup

Question

I am doing a research on getting the IDFA on iOS 14. I am using iPhone 8 Plus.

I have added

<key>NSUserTrackingUsageDescription</key>
<string>App would like to access IDFA for tracking purpose</string>

in the .plist file.

Then added

let type = ATTrackingManager.trackingAuthorizationStatus;

which returns .denied, having

func requestPermission() {
        ATTrackingManager.requestTrackingAuthorization { status in
            switch status {
            case .authorized:
                // Tracking authorization dialog was shown
                // and we are authorized
                print("Authorized")
            
                // Now that we are authorized we can get the IDFA
            print(ASIdentifierManager.shared().advertisingIdentifier)
            case .denied:
               // Tracking authorization dialog was
               // shown and permission is denied
                 print("Denied")
            case .notDetermined:
                    // Tracking authorization dialog has not been shown
                    print("Not Determined")
            case .restricted:
                    print("Restricted")
            @unknown default:
                    print("Unknown")
            }
        }
    }

But I'm getting .denied without any popup.

Do you know what is happening?

Answer 1

There's an option "Allow Apps to Request to Track" in system's Settings app, and if it's off, requestTrackingAuthorization will return .denied immediately.