Why Sometimes FCM Token is not getting generated?

[shasranj]

Sometimes when we delete the app FCM token is not getting generating. Can you please help what might be the possible cause of it?

Steps Which we are following:

1. Method swizzling is Enabled

2. In didFinishLaunchingWithOptions methods we are calling:

FirebaseApp.configure()
Messaging.messaging().delegate = self

UNUserNotificationCenter.current().delegate = self

3. Delegated is implemented, but sometimes not getting FCM token in it:

func messaging(_ messaging: Messaging, didReceiveRegistrationToken fcmToken: String?) {
debugPrint("Firebase registration token: (fcmToken)")
}

Also want to understand , what got changed in this version(Version 10.12.0 - July 11, 2023), FCM Token related.

[morganchen12]

The change in the changelog does not affect FCM token generation. Are you able to receive an APNs token? https://developer.apple.com/documentation/usernotifications/registering_your_app_with_apns

[morganchen12]

The APNs token must still be generated by the operating system before it can be associated with an FCM token. Do you have an APNs token?

[shasranj]

Q1.So are you suggesting we have to call UIApplication.shared.registerForRemoteNotifications() in didFinishLaunchingWithOptions methods to get APNs token ?
Q2. Also need to know do we need to call UIApplication.shared.registerForRemoteNotifications() every time on didFinishLaunchingWithOptions methods or just once in the mobile app lifecycle. ?

[morganchen12]

You should not do need to manually call that method. If you do, nothing bad happens. Yes, it should be called when your app is launched and only once for the app's entire lifetime. Are you receiving anything in this UIApplicationDelegate method if you implement it?

[shasranj]

Scenario 1:

1. Call UIApplication.shared.registerForRemoteNotifications()
2. didRegisterForRemoteNotificationsWithDeviceToken is getting called with apns token .

Scenario 2:

1. Didn't call UIApplication.shared.registerForRemoteNotifications()
2. didRegisterForRemoteNotificationsWithDeviceToken is not getting called .

So can you please suggest, to successfully generate FCM do we need to follow Scenario 1 Or Scenario 2 ?

[morganchen12]

Use scenario 1. Apologies, I mistakenly said you do not need to call registerForRemoteNotifications, which is wrong. Calling registerForRemoteNotifications is required.