I'm relative new to WP. I'm using Custom Post Type UI to manage my custom post types. I created a CPT "product" and I checked the "Built-in Taxonomies -> categories". I created some products and relative categories. I also set the option "Has Archive" to true. Following this documentation page in my theme folder I created a archive-product.php page with a single main loop like this:
<?php if (have_posts()) : while (have_posts()) : the_post(); ?> ....
but wordpress load always the archive page instead of this.