firebase token is null and token refresh is called continously in my testFlight - iphone

Question

First of all, i have no problem for FCM, firebase token is never null every time tokenRefreshNotification is called. But after, i add Google analytics, i got weird problem for Firebase token. Every time i turn off and turn on notification in my app settings used
UIApplication.shared.registerForRemoteNotifications()
my tokenRefreshNotification is called continously and it doesn't stop looping until i force close my apps. At first, my app crash, and when i try to trace it with NsLog, i found that Firebase token is null. The problem occurs only when i`m using my apps installed from TestFlight / production. When i try it from my Xcode builder, firebase token is null only once, but the second call, firebase token is exist and it stop working.
For google Analytics, it works fine and in my GoogleService-info.plist,
i have set IS_ANALYTICS_ENABLED to YES and IS_GCM_ENABLED to YES also. For the other, IS_ADS_ENABLED = YES, IS_APPINVITE_ENABLED = NO, and IS_SIGNIN_ENABLED = YES
func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplicationLaunchOptionsKey: Any]?) -> Bool {
FIRApp.configure()
NotificationCenter.default.addObserver(self, selector: #selector(self.registerNotification), name: NSNotification.Name(rawValue: "registerNotification"), object: nil)
NotificationCenter.default.addObserver(self, selector: #selector(self.tokenRefreshNotification(_:)), name: .firInstanceIDTokenRefresh, object: nil)
setupGoogleAnalytics()
return true
}
//when firebase token is null, this function is working continously until my firebase token is exist
func tokenRefreshNotification(_ notification: Notification) {
print("token Refresh")
if FIRInstanceID.instanceID().token() == nil{
NSLog("firebase token is null")
}
if (UserDefaults.standard.object(forKey: "id") != nil) && FIRInstanceID.instanceID().token() != nil{
FIRInstanceID.instanceID().getWithHandler({ (instanceID, error) in
NSLog("instanceID: \(instanceID!)")
//save firebase token to my database, sorry i can`t show it
})
}
// Connect to FCM since connection may have failed when attempted before having a token.
connectToFcm()
}
Note: At the first launch, i called my RegisterForRemoteNotifications, at TestFlight version, when tokenRefreshNotification is called, the firebase token is null, but the second call, firebase token is exist, so it could stop. But, when i run my app from Xcode, the first call is success because firebase token is not null.

Answer 1

i have figured it out! just change ANPS Type token from Sandbox to Unknown!
func application(_ application: UIApplication, didRegisterForRemoteNotificationsWithDeviceToken deviceToken: Data) {
// With swizzling disabled you must set the APNs token here.
FIRInstanceID.instanceID().setAPNSToken(deviceToken, type: FIRInstanceIDAPNSTokenType.unknown)
}