Problem send FCM notification unique token device

Good morning

I have implemented PUSH notifications in our app for both Android and iOS. I have used the Firebase platform.

I can send notifications to all subscribed apps without problem, both on Android and iOS, even on the Android side I manage to send to a single receiver using the device token. However, on the iOS side, I cannot send a single recipient using the token.
I have been looking for information for a few hours and I believe that the part of subscription to notifications and collection of the token are correct, however I send both from our server and from the Firebase console and the notifications never arrive.

My code for collecting the token is as follows:

           public override void RegisteredForRemoteNotifications(UIApplication application, NSData deviceToken)
            {
                {
                    var bytes = deviceToken.ToArray();
                    var oktoken= BitConverter.ToString(bytes).Replace("-", "");
                    token = oktoken;
                }
            }

I have seen several implementations but basically they are all the same and no different treatment is done.

The token I get on iOS is "E62289B322998781A2A630D10F562BC45BE9CC9835F060B324BE413EBD8E9373" but the token that gives me Andoroid contains more characters something like "dnK0atG1yZY: APa91bEWM8a-stgW6pd91aqIYs6v3qry1-y5ALaqqE-FKH6A4tU0I3oZvC6adqSnUdQOrrm-ou4ywiZY6oiM8itBOfjWN7FomuJFPhQVvnFK0ABawwCdxk5YaSmOBwMaKlB9yIwP-wF0" so I have the suspicion that the token that gives me iOS no It is correct although in theory it is so.
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Could someone with more experience in this help me?

I have already tried a thousand things and the fact that I send mass notifications and if they reach the part in iOS makes me think that the settings are correct, but I cannot guarantee it either.

I am debugging on a physical device with ios 13.5 installed

Does anyone think that they could review? Any help is welcome

greetings