Push Notification for iOS Device not working

Question

I have a question for the push notification fcm for iOS device from server side ASPNetCore Web api. When i send notification for the android device it was send successfully by using ServerKey and SenderID. But when i send the push notification for the iOS Device i got error BadDeviceToken although when i using fcm which i received from the client and send directly from firebase console it's work but only from the server side i got BadDeviceToken. Please can you tell me what is the problem is from server side?

      var apnSettings = new ApnSettings();
        apnSettings.ServerType = ApnServerType.Production;
        apnSettings.AppBundleIdentifier = _notificationSettings.AppBundleIdentifier;
        apnSettings.P8PrivateKey = _notificationSettings.P8PrivateKey;
        apnSettings.P8PrivateKeyId = _notificationSettings.P8PrivateKeyId;
        apnSettings.TeamId = _notificationSettings.TeamId;

Using Core Push Lib

thank you advance