Why URL address is repeating? – Plesk

I have website hosted over here: but when I login then the url into the address bar keeps repeating and getting longer like: this and here if you click on to the left side menu then you can see into the address bar that the URL keeps getting bigger and bigger. Please suggest me on the above why the URL is getting bigger like this?

please find the website credential as below:
username: int123
password: 123

Here is code sample:

           protected void Page_Load(object sender, EventArgs e)
    {
        if (!Page.IsPostBack)
        {
            if (Request.QueryString["type"] == "logout")
            {
                Session.Clear();
                Response.Cookies.Clear();
                //FormsAuthentication.SignOut();
                Response.Redirect("http://103.252.236.33/plesk-site-preview/2wayglobal.com/103.252.236.33/login.aspx");
            }
        }
    }

    protected void btnLogin_Click(object sender, EventArgs e)
    {
        string username = string.Empty;
        string userid = string.Empty;
        string address = string.Empty;
        string company = string.Empty;

        if ((txtUsername.Value.Trim() == string.Empty || txtUsername.Value.Trim() == "Username") && (txtPassword.Value.Trim() == string.Empty || txtPassword.Value.Trim() == "Password"))
        {
            //divError.Visible = true;
            lblError.Text = "Please type the correct username and password";
            ResetFields();
        }
        else if (txtUsername.Value.Trim() == string.Empty || txtUsername.Value.Trim() == "Username")
        {
            //divError.Visible = true;
            lblError.Text = "User name is incorrect.";
            ResetFields();
        }
        else if (txtPassword.Value.Trim() == string.Empty || txtPassword.Value.Trim() == "Password")
        {
            //divError.Visible = true;
            lblError.Text = "Password is incorrect.";
            ResetFields();
        }
        else
        {
            DataTable dtuserLogin = db.GetLoginDetails(txtUsername.Value.Trim(), txtPassword.Value.Trim());
            try
            {
                if (dtuserLogin.Rows.Count > 0)
                {
                    userid = Convert.ToString(dtuserLogin.Rows[0]["srno"]).Trim();
                    username = Convert.ToString(dtuserLogin.Rows[0]["username"]).Trim();
                    company = Convert.ToString(dtuserLogin.Rows[0]["company"]).Trim();
                    address = Convert.ToString(dtuserLogin.Rows[0]["address"]).Trim();
                    //FormsAuthentication.SetAuthCookie(username + ";" + company + ";" + address, true);
                }
            }
            catch (Exception ex)
            {
                throw new Exception("Error in btnLogin_Click()" + ex.Message);
            }

            if (username == "admin")
            {
                Response.Redirect("http://103.252.236.33/plesk-site-preview/2wayglobal.com/103.252.236.33/Admin/Default.aspx", true);
            }
            else
            {
                Response.Redirect("http://103.252.236.33/plesk-site-preview/2wayglobal.com/103.252.236.33/User/Default.aspx", true);
            }
        }
    }

    private void ResetFields()
    {
        txtUsername.Value = "Username";
        txtPassword.Value = "Password";
    }