MSSQL 2014 Connection and Socket Exception

Hello friends! Need your help!

I created database in MSSQLEXPRESS 2014 and trying to use this database in my Unity project. My code is below.

 using System.Collections;
 using System.Collections.Generic;
 using UnityEngine;
 using System.Data.SqlClient;
 public class GObj : MonoBehaviour {
 
     public void WorkWithDatabase()
     {
         string connectionstring = @"Data Source=127.0.0.1;Initial Catalog=GameForDiplom;Integrated Security=True;";
         
         SqlConnection Myconnection = new SqlConnection(connectionstring);
         Myconnection.Open();
         Debug.Log("OPEN SUCCESS!");
         
         using (var cmd = Myconnection.CreateCommand())
         {
             cmd.CommandText = @"SELECT * FROM [User]";
             using (var rdr = cmd.ExecuteReader())
             {
                 while (rdr.Read())
                 {
                     Debug.Log(rdr["IDuser"] + "\t" + rdr["Nickname"] + "\n");
                 }
             }
         }
 
         Myconnection.Close();
         Debug.Log("CLOSE SUCCESS!");
     }
 }

During connection to my database in game i receive this ERROR (In English-> SocketException:The connection is not established, since target machine actively refused the connection request.):

Please, I would like to see working code in C# and your settings of MSSQL EXPRESS 2014 which you use.

Thank you for help, Friends!