I’m following this tutorial https://learn.microsoft.com/ja-jp/previous-versions/dotnet/spark/tutorials/get-started?tabs=windows to try to test
.Net Spark from Visual Studio.
But at the very begining, got error “System.Net.Sockets.SocketException: The connection was refused by target computer. 127.0.0.1:5567”.
Tried different port number but the simillar error message again and again.
OS: Windows11.
What’s wrong in here?

using Microsoft.Spark.Sql;
using System;
using Newtonsoft.Json.Linq;
using static Microsoft.Spark.Sql.Functions;

namespace MySparkApp
{
    class Program
    {
        static void Main(string[] args)
        {
            //Environment.SetEnvironmentVariable("DOTNETBACKEND_PORT", "56511");

            // Create Spark session
            SparkSession spark =
                SparkSession                    
                    .Builder()
                    .AppName("word_count_sample")                    
                    .GetOrCreate();

            // Create initial DataFrame
            string filePath = args[0];
            DataFrame dataFrame = spark.Read().Text(filePath);

            //Count words
            DataFrame words =
                dataFrame
                    .Select(Split(Col("value"), " ").Alias("words"))
                    .Select(Explode(Col("words")).Alias("word"))
                    .GroupBy("word")
                    .Count()
                    .OrderBy(Col("count").Desc());

            // Display results
            words.Show();

            // Stop Spark session
            spark.Stop();
        }
    }
}