NRE on FirebaseCloudMessagingImplementation.Initialize();

[IvanFMit]

I get the following error when running the method FirebaseCloudMessagingImplementation.Initialize();

this is my code:
events.AddiOS(iOS => iOS.WillFinishLaunching((_,__) => { try{ CrossFirebase.Initialize(); FirebaseCloudMessagingImplementation.Initialize(); } catch(Exception ex) { //Exception Here } return false; }));

This is the Exception

System.NullReferenceException: Object reference not set to an instance of an object.
at Plugin.Firebase.CloudMessaging.FirebaseCloudMessagingImplementation.RegisterForRemoteNotifications()
at Plugin.Firebase.CloudMessaging.FirebaseCloudMessagingImplementation.Initialize()
at visitor.manager.maui.app.MauiProgram.<>c.b__6_3(UIApplication _, NSDictionary __) in /Users/eyleenecheverry/AppsIvan/visitor.manager-mobile/visitor.manager.maui/MauiProgram.cs:line 86

Help please