No statistics on a website joomla

I’ve been using matomo for several years in the Basque way for associative sites created with joomla.
I don’t understand why, I don’t get any statistics on a site after inserting the code.

The url is on the pages and I can see its content by clicking on the source code link:
I just inserted this code yesterday.
The code mentions the right; id=8

  var _paq = window._paq = window._paq || [];
  /* tracker methods like "setCustomDimension" should be called before "trackPageView" */
  (function() {
    var u="";
    _paq.push(['setTrackerUrl', u+'matomo.php']);
    _paq.push(['setSiteId', '8']);
    var d=document, g=d.createElement('script'), s=d.getElementsByTagName('script')[0];
    g.async=true; g.src=u+'matomo.js'; s.parentNode.insertBefore(g,s);

An idea to solve the problem ?