host '' for user '' using method 'mysql_native_password' failed with message: Access denied for user ''@***' (using password: NO)

        DataSet1 ds = new DataSet1();

        Conn = new MySqlConnection();
        //    Conn.Open();


       MySqlDataAdapter da = new MySqlDataAdapter("sp_rpt_Show_User_Details", Conn);

        da.SelectCommand.CommandType = CommandType.StoredProcedure;
        ReportDocument myrpt = new ReportDocument();
        da.Fill(ds.agenthistorycumulative);


        myrpt.Load(Server.MapPath("~/CrystalReport2.rpt"));
        CrystalReport2 c = new CrystalReport2();
        c.SetDataSource(ds);
        CrystalReportViewer1.ReportSource = c;

if i comment the da.fill method..that time show the report but didnt show data..only table fields name...if i uncomment the da.fill() method then give the Authentication to host '' for user '' ...msg....help me