Roles.IsUserInRole not working

 

protected void GridView1_RowDataBound(object sender, GridViewRowEventArgs e)
        {
            if (e.Row.RowType == DataControlRowType.DataRow)
            {
                if (Roles.IsUserInRole("Cre")) // when i execute it it, it wont run this line even is logged as Cre role user
                {
                    Button btnEdit = e.Row.FindControl("Button11") as Button;
                    Button btnDelete = e ...