xamarin project suavecontrols referenced in xamarin can be modified in c# but not in xaml

I use a materialentry from the project suavecontrols which link is this https://github.com/SuavePirate/SuaveControls.MaterialFormControls

The problem is the next, if I use the control in C# there is no problem and works

using System;using System.Collections.Generic;using System.Linq;using System.Text;using System.Threading.Tasks;using Xamarin.Forms;using SuaveControls.MaterialEntry;namespace add_suave_control{public partial class MainPage : ContentPage{    public MainPage()    {        InitializeComponent();        var suavecito = new SuaveControls.MaterialEntry.MaterialEntry        {            BackgroundColor = Color.Green,            Placeholder = "Escribe",        };        Content = new StackLayout        {            VerticalOptions = LayoutOptions.Center,            Spacing = 10,            Children = { suavecito },        };        //si agrego controles por c# no hay problema, pero si lo hago por xaml entonces sí    }}}

But if I try the same in xaml with this code it doesn't work

<?xml version="1.0" encoding="utf-8" ?><ContentPage xmlns="http://xamarin.com/schemas/2014/forms"         xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"         xmlns:local="clr-namespace:add_suave_control"         x:Class="add_suave_control.MainPage"         xmlns:suave="clr-namespace:SuaveControls.MaterialEntry;assembly=SuaveControls.MaterialEntry"><suave:MaterialEntry BackgroundColor="Green" Placeholder="PorMientras"></suave:MaterialEntry></ContentPage>

For use MaterialEntry I add a reference in Android and pcl to SuaveControls.MaterialEntry.dll and SuaveControls.MaterialEntry.Android.dll