Remote Push Notification with Firebase

Hi,
I am having trouble figuring out the issue with remote push notification. I see a success message in my sendPushNotification.

func sendPushNotification(to token: String, title: String, body: String) {
        let urlString = "https://fcm.googleapis.com/fcm/send"
        let url = NSURL(string: urlString)!
        let paramString: [String : Any] = ["to" : token,
                                           "notification" : ["title" : title, "body" : body],
                                           "data" : ["user" : "test_id"]
        ]
        let request = NSMutableURLRequest(url: url as URL)
        request.httpMethod = "POST"
        request.httpBody = try? JSONSerialization.data(withJSONObject:paramString, options: [.prettyPrinted])
        request.setValue("application/json", forHTTPHeaderField: "Content-Type")
        request.setValue("key="+Constants.CloudMessaging.key, forHTTPHeaderField: "Authorization")
        let task =  URLSession.shared.dataTask(with: request as URLRequest)  { (data, response, error) in
            do {
                if let jsonData = data {
                    if let jsonDataDict  = try JSONSerialization.jsonObject(with: jsonData, options: JSONSerialization.ReadingOptions.allowFragments) as? [String: AnyObject] {
                        NSLog("Received data:\n\(jsonDataDict))")
                    }
                }
            } catch let err as NSError {
                print(err.debugDescription)
            }
        }
        task.resume()
    }

However, the device receives no notification. Not sure what am I doing wrong.
This is my complete receive side code

    var userNotificationService = UserNotificationService()
    let userID: String
    init(userID: String) {
        self.userID = userID
        super.init()
    }
    func registerForPushNotifications() {
        Messaging.messaging().delegate = self
        if #available(iOS 10.0, *) {
            // For iOS 10 display notification (sent via APNS)
            UNUserNotificationCenter.current().delegate = self
            let authOptions: UNAuthorizationOptions = [.alert, .badge, .sound]
            UNUserNotificationCenter.current().requestAuthorization(
                options: authOptions,
                completionHandler: {_, _ in })
            // For iOS 10 data message (sent via FCM)
            
        } else {
            let settings: UIUserNotificationSettings =
                UIUserNotificationSettings(types: [.alert, .badge, .sound], categories: nil)
            UIApplication.shared.registerUserNotificationSettings(settings)
        }
        
        DispatchQueue.main.async {
            UIApplication.shared.registerForRemoteNotifications()
        }
        updateFirestorePushTokenIfNeeded()
    }
    func updateFirestorePushTokenIfNeeded() {
        if let token = Messaging.messaging().fcmToken {
            var data = UserNotification()
            data.fcmToken = token
            data.playerID = userID
            data.id = userID
            userNotificationService.updateToken(data)
            
        }
    }
    func messaging(_ messaging: Messaging, didReceive remoteMessage: MessagingRemoteMessage) {
        print("value:")
        print(remoteMessage.appData)
    }
    func messaging(_ messaging: Messaging, didReceiveRegistrationToken fcmToken: String) {
        updateFirestorePushTokenIfNeeded()
        let dataDict:[String: String] = ["token1": fcmToken ?? ""]
        print("value2:")
        print(dataDict)
    }
    
}

@available(iOS 10, *)
extension PushNotificationManager: UNUserNotificationCenterDelegate {
    
    func userNotificationCenter(_ center: UNUserNotificationCenter,
                                willPresent notification: UNNotification,
      withCompletionHandler completionHandler: @escaping (UNNotificationPresentationOptions) -> Void) {
        print(notification)
      // Change this to your preferred presentation option
        completionHandler([[.banner, .badge, .sound]])
    }

    func userNotificationCenter(_ center: UNUserNotificationCenter, didReceive response: UNNotificationResponse, withCompletionHandler completionHandler: @escaping () -> Void) {
        print(response)
        completionHandler()
    }
}

I also uploaded .p12 on firebase and enabled push notification on my apple account.
I am happy to pair up with someone who has this working,

Much appreciate it,