Error passing parameter to function

I've lost full access to my sites and am trying to pass the posts on it to a new one. I have a code that reads the sitemap from it and takes the urls and another one that catches the url , separates the part that I need and put in my new site.

static void Main(string[] args)
{
    var website = XMLReader("SITE");
    Postagem(website.ToString());
    Console.WriteLine("Total de Posts adicionados: " + website.Count());
    Console.ReadLine();
}

When passing these urls to the function XMLReader , with Postagem , it returns me the error:

  

Error: System.UriFormatException: Invalid URI: The format of the URI could not be determined.

But if I pass:

Postagem("LINK DO POST");

He puts everything right. What would be the mistake? I did not find anything on the net.

private static void Postagem(string website)
{
    try
    {
        string link = "SITE";
        string username = "USER_WP";
        string password = "SENHA_WP";
        HtmlWeb web = new HtmlWeb();
        HtmlDocument resultat = web.Load(website);
        string titulopost = resultat.DocumentNode.SelectNodes("//*[contains(@class,'entry-title')]")[0].InnerHtml;
        string conteudo = resultat.DocumentNode.SelectNodes("//*[contains(@class,'entry-content')]")[0].InnerHtml;
        var wp = new WordPressWrapper(link + "/xmlrpc.php", username, password);
        var post = new Post();
        Console.WriteLine("Adicionando post: " + titulopost);

        post.DateCreated = DateTime.Today.AddHours(0);
        post.Title = titulopost;
        post.Body = conteudo;

        wp.NewPost(post, true);
    }
    catch (Exception e)
    {
        Console.WriteLine("Error: {0}", e);
    }
}