Login problem , shows error page

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C#

ASP.NET

SQL-Server

Login is my default start page in my project.after login only website visible,otherwise goes to error page.

in my question i have username password and isctive in my databse,but always error page only visible

What I have tried:

<pre>using System;
using System.Collections;
using System.Configuration;
using System.Data;
using System.Linq;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.HtmlControls;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Xml.Linq;
using System.Data.SqlClient;

public partial class Login : System.Web.UI.Page
{
    SqlConnection con = new SqlConnection(ConfigurationManager.ConnectionStrings["constr"].ConnectionString);
    protected void Page_Load(object sender, EventArgs e)
    {
        try
        {
            if (!Page.IsPostBack)
            {
                if (Request.QueryString.Count > 0)
                {
                    string UserID = Request.QueryString["UserID"];
                    Session["UserID"] = UserID;
                    Response.Redirect("Default.aspx",false);
                }
            }
        }
        catch (Exception ex)
        {
            Session["Error"] = ex.ToString();
            Response.Redirect("Error.aspx");
        }
    }
    protected void btnLogin_Click(object sender, EventArgs e)
    {
        try
        {
            if (CheckUsername())
            {
                if (CheckPassword())
                {
                    RedirectPage();
                }
                else
                {
                    lblError.Text = "Your login attempt has failed. <BR>Please try again!";
                }
            }
            else
            {
                lblError.Text = "Your login attempt has failed. <BR>The username or password may be incorrect";
            }
        }
        catch (Exception ex)
        {
            Session["Error"] = ex.ToString();
            Response.Redirect("Error.aspx");
        }
    }
    public bool CheckUsername()
    {
        string Query = "select * from users where IsActive='True' and Email='" + txtUserName.Text + "'";
        DataTable dt = GetData(Query);
        if (dt.Rows.Count > 0)
            return true;
        else
            return false;
    }
    public bool CheckPassword()
    {
        string Query = "select * from users where IsActive='True' and Email='" + txtUserName.Text + "' and Password='"+txtPassword.Text+"'";
        DataTable dt = GetData(Query);
        if (dt.Rows.Count > 0)
            return true;
        else
            return false;
    }
    public DataTable GetData(string Query)
    {
        SqlCommand cmd = new SqlCommand(Query, con);
        SqlDataAdapter sda = new SqlDataAdapter(cmd);
        DataTable dt = new DataTable();
        sda.Fill(dt);
        return dt;
    }
    public void RedirectPage()
    {
        string Query = "select top(1) * from users where IsActive='True' and Email='" + txtUserName.Text + "' and Password='" + txtPassword.Text + "'";
        DataTable dt = GetData(Query);
        if (dt.Rows.Count == 1)
        {
            Session["UserID"] = dt.Rows[0]["UserID"].ToString();
            Response.Redirect("Home.aspx", false);
        }
        else
        {
            lblError.Text = "You don't have permission to view this Site!";
            Session["UserID"] = "";
        }
        /*if (dt.Rows.Count == 1)
        {
            if (Convert.ToBoolean(dt.Rows[0]["Products"]) == true && Convert.ToBoolean(dt.Rows[0]["Users"]) == true)
            {
                Session["UserID"] = dt.Rows[0]["UserID"].ToString();
                Response.Redirect("Default.aspx", false);
            }
            else if (Convert.ToBoolean(dt.Rows[0]["Products"]) == true && Convert.ToBoolean(dt.Rows[0]["Users"]) == false)
            {
                Session["UserID"] = dt.Rows[0]["UserID"].ToString();
                Response.Redirect("Default.aspx", false);
            }
            else if (Convert.ToBoolean(dt.Rows[0]["Products"]) == false && Convert.ToBoolean(dt.Rows[0]["Users"]) == true)
            {
                Session["UserID"] = dt.Rows[0]["UserID"].ToString();
                Response.Redirect("Users.aspx", false);
            }
            else
            {
                Session["UserID"] = "";
                Response.Redirect("Login.aspx", false);                
            }            
        }
        else
        {
            lblError.Text = "You don't have permission to view this Site!";
            Session["UserID"] = "";
        }*/
    }
}