controller_action_postdispatch_checkout_cart_add event is not firing

This is my first time playing around with Magento. I’m building a module and I want to listen when a product is added to the cart so, I’ve tried to use the controller_action_postdispatch_checkout_cart_add event but it doesn’t seem to be firing.

In the events.xml file I have:

<?xml version="1.0"?>
<config xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="urn:magento:framework:Event/etc/events.xsd">
   <event name="catalog_controller_product_view">
        <observer name="test_mymodule_catalog_controller_product_view" instance="TestMyModuleObserverCatalogProductView" />
    </event>
    <event name="controller_action_postdispatch_checkout_cart_add">
        <observer name="test_mymodule_controller_action_postdispatch_checkout_cart_add" instance="TestMyModuleObserverControllerAddToCart" />
    </event>
</config>

and in the observer file, I have the following code:

<?php
namespace TestMyModuleObserver;

use MagentoFrameworkEventObserver;
use MagentoFrameworkEventObserverInterface;
use MagentoStoreModelStoreManagerInterface;

class ControllerAddToCart implements ObserverInterface
{
    protected $storeManager;

    public function __construct(
        StoreManagerInterface $storeManager
    ) {
        $this->storeManager = $storeManager;
    }

    public function execute(Observer $observer) {
        var_dump('hello ATC');
        $console = '<script>console.log("action ATC");</script>';
        echo $console;
        $currency = $this->storeManager->getStore()->getCurrentCurrencyCode();
        $consoleCurrency = '<script>console.log("'. $currency .'");</script>';
        echo $consoleCurrency;
    }
}

I know my module is enabled and it is working fine because I also added the catalog_controller_product_view event and this one is firing.

I have to mention that I’ve tried the checkout_cart_add_product_complete event, checkout_cart_save_after and checkout_cart_product_add_after. None of these work for me.

Also, not sure if it’s relevant to say that I installed the Magento store following the instructions from here and the store has the Luma theme installed.

p.s: I don’t see any errors in the console

Thanks in advance to all.