As we have previously mentioned, nRF Connect is the the best app for detecting if a Bluetooth LE device such as a beacon is working. The Android version has always had more features than the iOS version but that is changing. nRF Connect for iOS has been completely re-written and now has a very pretty UI.
We still recommend using the Android rather than the iOS version because iOS apps can’t see Bluetooth MAC addresses due to some peculiar decisions made by people at Apple. Scanning also can’t see an iBeacon UUID, major and minor in the advertising. It’s more difficult to uniquely identify Bluetooth devices in apps such as nRF Connect on iOS than it is on Android.