在sqlCon.open语句中出现错误；System.Data.SqlClient.SqlException'；发

public partial class Webpages_Default : System.Web.UI.Page
{
    SqlConnection sqlCon = new SqlConnection(ConfigurationManager.ConnectionStrings["conStr"].ConnectionString);
    protected void Page_Load(object sender, EventArgs e)
    {
        lblnorecordfound.Visible = false;
        gvRCATracker.Visible = false;
        if (!IsPostBack) {
            //Binding control
            sqlCon.Open();
            BindPriority();
            BindProductCategory();
            BindPortfolio();
            BindRCAResponseTeam();
            BindTSMReview();
            BindRCAStatus();
            sqlCon.Close();
            SetReadOnlyForDateControls();
        }               
    }
}