Cannot run database when convert to exe or play in android devices?

Hi all, im trying to make online game. i already can connect to online MySQL server.

When i test it on game view in unity it's working, but when i convert it into exe or when i played in my android devices it's not working.

Can anyone tell me why it's not working when i played it in exe or in my mobile device?

This is my code :

 using UnityEngine;
 using System.Collections;
 using System.Data;
 using MySql.Data.MySqlClient;
 
 public class DatabaseCS : MonoBehaviour {
     
     private static IDbConnection dbConnection;
     
     // Use this for initialization
     void Start () {
         
     }
     
     public void OnGUI () {
         openSqlConnection();
         
         IDataReader  reader = doQuery("SELECT Name FROM unity3d WHERE Name = 'Cube'");
         
         while (reader.Read()) {
 
             string myVar = (string) reader["Name"];
             GUI.Button(new Rect(Screen.width / 2 - 50,Screen.height / 2 - 50,100,30), myVar);
         }
         
     }
     
     public void OnApplicationQuit() {
 
         closeSqlConnection();
 
     }
     
     private static void openSqlConnection() {
         
         print ("Open");
         
         string connectionString = 
             
             "Server=myserver;" +
 
             "Database=mydatabase;" +
 
             "User ID = myuser;" +
 
             "Password=mypassword;" +
 
             "Pooling=false";
 
         dbConnection = new MySqlConnection(connectionString);
 
         dbConnection.Open();
 
         Debug.Log("Connected to database.");
 
     }
     
     private static void closeSqlConnection() {
 
         dbConnection.Close();
 
         dbConnection = null;
 
         Debug.Log("Disconnected from database.");
 
     }
     
     public static IDataReader doQuery(string sqlQuery) {
 
         IDbCommand dbCommand = dbConnection.CreateCommand();
     
         dbCommand.CommandText = sqlQuery;
     
         IDataReader reader = dbCommand.ExecuteReader();
     
         dbCommand.Dispose();
     
         dbCommand = null;
     
         return reader;
 
     }
 
     
     // Update is called once per frame
     void Update () {
     
     }
 }

Thanks