Why don't optimize.google.com experiments work?

Question

Google

Created yesterday 2 experiments on https://optimize.google.com/
So far, the statistics are empty.. as if the experiments are not running.

What is the problem?
On the right, the "Install Optimize snippet" item is inactive.
It has this code:

<script>
  (function(i,s,o,g,r,a,m){i['GoogleAnalyticsObject']=r;i[r]=i[r]||function(){
  (i[r].q=i[r].q||[]).push(arguments)},i[r].l=1*new Date();a=s.createElement(o),
  m=s.getElementsByTagName(o)[0];a.async=1;a.src=g;m.parentNode.insertBefore(a,m)
  })(window,document,'script','https://www.google-analytics.com/analytics.js','ga');
  ga('create', 'UA-3289501-52', 'auto');
  ga('require', 'GTM-KLT8VQQ');
  ga('send', 'pageview');
</script>

As I understand it, you need to add only this line to the code on the site:
ga('require', 'GTM-KLT8VQQ');
My site is https://expert-obzor.ru/
Analytics is connected to it through the tag manager with the following code:

<script type="text/javascript">
    var _gaq = _gaq || [];
    _gaq.push(['_setAccount', 'UA-3289501-52']);
    _gaq.push(['_trackPageview']);
    ga('require', 'GTM-KLT8VQQ');

    (function() {
        var ga = document.createElement('script'); ga.type = 'text/javascript'; ga.async = true;
        ga.src = ('https:' == document.location.protocol ? 'https://ssl' : 'http://www') + '.google-analytics.com/ga.js';
        var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(ga, s);
    })();
    </script>

I added a line inside, but it doesn't help..
ga('require', 'GTM-KLT8VQQ');
What's the matter??

Answer 1

You have some kind of porridge. First, you take the Universal GA code, then write that your GA is implemented through GTM, the code of which, by the way, is completely different, and not the one you wrote ... Where you added the line is not clear at all ... It's not even clear how to help. First, figure out how your GA is connected.
Connection manual here - https://support.google.com/360suite/optimize/answe...
The page is only in English so far. There are requirements:
Complete the steps in the Set up Optimize article.
That is, it only works with new code. The old code will not work.