data base is not connected .is there any mistake in my code

protected void Button1_Click(object sender, EventArgs e)
    {

        SqlConnection conn = new SqlConnection(@"Data Source=(LocalDB)\v11.0;AttachDbFilename=E:\gnani\websites\iconlabssite part2\App_Data\maindatabase.mdf;Integrated Security=True;");
        SqlCommand insert = new SqlCommand("insert into regform(username, password, mobileno,emailid) values(@username, @password, @phoneno,@emailid)", conn);
        insert.Parameters.AddWithValue("@username", TextBox1.Text);
        insert.Parameters.AddWithValue("@password", TextBox2.Text);
        insert.Parameters.AddWithValue("@phoneno", TextBox4.Text);
        insert.Parameters.AddWithValue("@emailid", TextBox5.Text);
        try
        {
            conn.Open();
            insert.ExecuteNonQuery();
        }
        catch (Exception ex)
        {
            LMsg.ForeColor = System.Drawing.Color.Red;
            LMsg.Text = "Error when saving on database";
            conn.Close();
        }
        TextBox1.Text = "";
        TextBox2.Text = "";
        TextBox3.Text = "";
        TextBox4.Text = "";
        TextBox5.Text = "";
        TextBox6.Text = "";
    }