WordPress get_template_part not working – returns 404 page instead of loop-xxx.php

Usually I try my best to find answers by searching online or endless experimenting. This time I’m really desperate. I have read many related questions but none has the solution to my problem.

I use ‘get_template_part’ in many other themes and it worked well. This time I don’t know what made the difference.

In my theme there is a registered custom post type event. The url of a post in event would look like example.com/event/wine-tasting.

The problem is: example.com/event/ returns a 404 page instead of lining up all event posts (loop-event.php)

Here is my archive.php:

<?php get_header(); ?>
<?php if ( have_posts() ) the_post();?>
<?php rewind_posts();?>
<?php $post_type = get_post_type();
    get_template_part( 'loop', $post_type );?>
<?php get_footer(); ?>

Here is my loop-event.php:

<?php get_header(); ?>
<?php if ( have_posts() ) while ( have_posts() ) : the_post(); ?>
    <div class="container">
        <?php the_title();?>
        <?php the_content();?>
    </div>
<?php endwhile; ?>

This is how I register the custom post type ‘event’:

function yd_create_post_type_event() 
{
$labels = array(
    'name' => __( 'Events','yd'),
    'singular_name' => __( 'Event','yd' ),
    'add_new' => __('Add New','yd'),
    'add_new_item' => __('Add New Event','yd'),
    'edit_item' => __('Edit Event','yd'),
    'new_item' => __('New Event','yd'),
    'view_item' => __('View Event','yd'),
    'search_items' => __('Search Event','yd'),
    'not_found' =>  __('No event found','yd'),
    'not_found_in_trash' => __('No event found in Trash','yd'), 
    'parent_item_colon' => ''
  );

  $args = array(
    'labels' => $labels,
    'public' => true,
    'exclude_from_search' => false,
    'publicly_queryable' => true,
    'show_ui' => true, 
    'show_in_menu' => true,
    'show_in_admin_bar' => true,
    'query_var' => true,
    'capability_type' => 'post',
    'hierarchical' => false,
    'menu_position' => 5,
    'menu_icon' => 0,
    'supports' => array('title','editor','excerpt')

  ); 

 register_post_type('event',$args);
}

register_taxonomy(
    "event-category", 
    array("event"), 
    array(
        "hierarchical" => true, 
        "label" => __( "Event Categories",'yd' ), 
        "singular_label" => __( "Event Category",'yd' ), 
        "rewrite" => array('slug' => 'event')
    )
); 

I would really appreciate your help. I have tried everything and I wish it was me who made some dumb mistakes. But I couldn’t work it out so far. Thank you in advance!