'converters' is an undeclared prefix. Line 8, position 14.

<?xml version="1.0" encoding="utf-8" ?>
<ContentPage xmlns="http://xamarin.com/schemas/2014/forms"
             xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
             x:Class="Historation.Views.NewPartPage"
             xmlns:converter="clr-namespace:App.Converter">
    <ContentPage.Resources>
        <ResourceDictionary>
            <converters:IntEnumConverter x:Key="IntEnum"/> //<- error on this line
        </ResourceDictionary>
    </ContentPage.Resources>

namespace App.Converter
{
    public class IntEnumConverter : IValueConverter
    {
        public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
        {
            if (value is Enum)
            {
                return (int)value;
            }
            return 0;
        }

        public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture)
        {
            if (value is int)
            {
                return Enum.ToObject(targetType, value);
            }
            return 0;
        }
    }
}