How to make YAN ads appear after (cycle) every three posts?

Question

contextual advertising

Good day.
You need to do something like this, only with YAN from Yandex

. Now the following is obtained,

that is, now it is displayed only after the second post, and then the block under YAN is empty. and does not want to be displayed.
The blocks themselves are displayed like this

<?php if ( $postcounter % 6 == 2 ) : ?>
<?php get_template_part('loop', 'reklama' ); ?>
          <?php endif ?>

<div class="item reklama">
            <div class="wrap">
<!-- Yandex.RTB R-A-327587-1 -->
<div id="yandex_rtb_R-A-327587-1"></div>
<script type="text/javascript">
    (function(w, d, n, s, t) {
        w[n] = w[n] || [];
        w[n].push(function() {
            Ya.Context.AdvManager.render({
                blockId: "R-A-327587-1",
                renderTo: "yandex_rtb_R-A-327587-1",
                async: true
            });
        });
        t = d.getElementsByTagName("script")[0];
        s = d.createElement("script");
        s.type = "text/javascript";
        s.src = "//an.yandex.ru/system/context.js";
        s.async = true;
        t.parentNode.insertBefore(s, t);
    })(this, this.document, "yandexContextAsyncCallbacks");
</script>
            </div>
          </div>

Answer 1

Googled poke

Answer 2

if the ad block code is in a loop, then you have several blocks with the same id displayed.