[lazarus] why sometime TLHTTPClientComponent can not get data?

[wfifi]

some url can get data(example: http://www.google.com/ ), some others
can't(example: http://anime.xunlei.com/Book/category/610), all url can
browsered by ie or firefox.
how debug can find the reasons?
partly my code:

procedure TFormMain.MenuItemNewStoryClick(Sender: TObject);
var
  Urlstr: String;
  aHost, aURI: string;
  aPort: Word;
  node: TTreeNode;
begin
  Urlstr := InputBox('Input Comic Story Url',
    'Please input comic story url',
    'http://anime.xunlei.com/Book/category/610');
  if (Urlstr<>'') and (Urlstr<>'http://') then
    begin
      HTTPClient.Disconnect();
      strstream:= TStringStream.Create('');
      DecomposeURL(Urlstr, aHost, aURI, aPort);
      HTTPClient.Host := aHost;
      HTTPClient.URI  := aURI;
      HTTPClient.Port := aPort;
      HTTPClient.SendRequest;
      StatusBar.SimpleText := 'Connect...';
    end
  else
    //ShowMessage('Invalid Url');
end;

function TFormMain.HttpClientInput(ASocket: TLHTTPClientSocket; ABuffer:
pchar;
  ASize: integer): integer;
var
  oldLength: integer;
begin
     StatusBar.SimpleText := 'input...';
     strstream.WriteString(String(ABuffer));
     StatusBar.SimpleText := IntToStr(ASize) + '...';
     Result := ASize; // tell the http buffer we read it all
end;