IOS Push-notification not working IOS but works on Android.

We have followed this tutorial -- Push Notifications For iOS to test pushing notifications for iOS. It works fine, the alert message would pop up when the application starts. After users choose "allow to push notification", the application can go on. The Client API RegisterForIOSPushNotification and SendPushNotification both can work. We also test to use this sample with the Unity Mobile Notifications Plugin, it works fine too. You can try to refer to the following sample code.

using System.Collections;
using PlayFab;
using PlayFab.ClientModels;
using Unity.Notifications.iOS;
using UnityEngine;


public class TestNotification : MonoBehaviour
{
    void Start()
    {
        StartCoroutine(RequestAuthorization());
    }


    IEnumerator RequestAuthorization()
    {
        using (var req = new AuthorizationRequest(AuthorizationOption.Alert | AuthorizationOption.Badge, true))
        {
            while (!req.IsFinished)
            {
                yield return null;
            };


            string res = "\n RequestAuthorization: \n";
            res += "\n finished: " + req.IsFinished;
            res += "\n granted :  " + req.Granted;
            res += "\n error:  " + req.Error;
            res += "\n deviceToken:  " + req.DeviceToken;
            Debug.Log(res);


            PlayFabClientAPI.LoginWithCustomID(new LoginWithCustomIDRequest
            {
                CustomId = "[YourCustomId]",
                CreateAccount = true,
                TitleId = PlayFabSettings.TitleId


            }, OnLoginSuccess, OnPlayFabError);
        }


    }


    private void OnLoginSuccess(LoginResult obj)
    {
        byte[] token = UnityEngine.iOS.NotificationServices.deviceToken;
        if (token != null)
        {
            RegisterForIOSPushNotificationRequest request = new RegisterForIOSPushNotificationRequest();
            request.DeviceToken = System.BitConverter.ToString(token).Replace("-", "").ToLower();
            PlayFabClientAPI.RegisterForIOSPushNotification(request, (RegisterForIOSPushNotificationResult result) =>
            {
                Debug.Log("Push Registration Successful");
            }, OnPlayFabError);
        }
        else
        {
            Debug.Log("Push Token was null!");
        }
    }


    private void OnPlayFabError(PlayFabError error)
    {
        Debug.Log(error.GenerateErrorReport());
    }
}

For more advanced questions about Unity Notification Plugins, please navigate to the Unity forum for professional supports. For more information on how to send push notifications to a device and how to add push notification support to your app, see the Apple Developer website documentation.