Promokit Helpdesk Alysum

The categories are not displayed in the AMP site. All permissions are set correctly and ssl and https are ok.
As you can see in the attached file, it seems that the AMP template is not parsed by the proper engine as the following slice of code appears in the resulting HTML output:
<template type=”amp-mustache”>

  
<article class="product-miniature relative m40 {{has_discount}}" data-id="{{id_product}}">

  <a href="{{amp_link}}" title="{{name}}">
    <amp-img src="{{cover.medium.url}}" width="{{cover.medium.width}}" height="{{cover.medium.height}}" layout="responsive" class="product-image-amp" alt="{{name}}"></amp-img>
    <ul class="product-labels">
              {{#discount_amount_to_display}}
      <li class="discount-amount discount-product">{{discount_amount_to_display}}
      </li>
      {{/discount_amount_to_display}}
      
      <li>{{flags.new.label}}</li>

              {{#quantity_all_versions}}
        <li>Out of Stock</li>
      {{/quantity_all_versions}}
            </ul>
  </a>

      <div class="product-price-amp price m15 flex-container">
    {{#has_discount}}
    <span class="discount-price">
      <span class="regular-price">{{regular_price}}</span>
    </span>
    {{/has_discount}}
    <span>{{price}}</span>
  </div>
  
  <div class="width-float ellipsis product-title m15">
    <a href="{{amp_link}}" title="{{name}}">{{name}}</a>
  </div>

      <form method="POST" action-xhr="//www.relaxstore.it/module/pk_amp/ajaxCart?who=category-add_to_cart" target="_top" class="flex-container align-items-center" on="submit-success: AMP.setState({ cartList: { items: event.response.items, info: event.response.info } });">

    <input type="hidden" name="act" value="up">
    <input type="hidden" name="do" value="cartUpdate">
    <input type="hidden" name="id_product" value="{{id_product}}">
    <input type="hidden" name="id_product_attribute" value="{{id_product_attribute}}">
    <button type="submit" class="add-to-cart big-btn">Aggiungi al carrello</button>

    <div submit-success><div class="flex-container align-items-center"><span>Successo&nbsp;</span><amp-bodymovin-animation layout="flex-item" width="34" height="34" src="https://www.relaxstore.it/themes/alysum/templates/mobile/assets/json/success.json" loop="false"></amp-bodymovin-animation></div></div>
    <div submit-error>Impossibile aggiungere al carrello</div>
    <div submitting>In attesa...</div>

  </form>
  
</article>

</template>