Bootstrap 4 Slider with WordPress

front-page.php

 <div id="main-slider" class="carousel slide mt-4" data-ride="carousel">

             <?php $args = array(
                'posts_per_page' => 5,
                'tag' => 'slider'
             );
             $slider = new WP_Query($args);
             if($slider->have_posts()):
             $count = $slider->found_posts;
             ?>
                <ol class="carousel-indicators">
                   <?php for($i = 0; $i < $count ;  $i++) { ?>
                          <li data-target="#main-slider" data-slide-to="<?php echo $i; ?>" class="<?php echo ($i == 0) ? 'active' : ''?>"></li>
                    <?php } ?>
                </ol> <!--.carousel-indicators-->

                <div class="carousel-inner" role="listbox">
                   <?php $i = 0; while($slider->have_posts()): $slider->the_post(); ?>
                       <div class="carousel-item <?php echo ($i == 0) ? 'active' : ''?>">
                             <?php the_post_thumbnail( 'slider', array(
                                                                     'class' => 'd-block img-fluid',
                                                                     'alt' => get_the_title() ) ) ; ?>
                             <div class="carousel-caption d-none d-md-block">
                                 <h3 class="text-uppercase"><?php echo get_the_content(); ?></h3>
                             </div>
                       </div><!--.carousel-item-->
                    <?php $i++; endwhile; ?>
                </div> <!--.carouse-inner-->


                <a href="#main-slider" class="carousel-control-prev" data-slide="prev">
                    <span class="carousel-control-prev-icon" aria-hidden="true"></span>
                    <span class="sr-only">Previous</span>
                </a>
                <a href="#main-slider" class="carousel-control-next" data-slide="next">
                    <span class="carousel-control-next-icon" aria-hidden="true"></span>
                    <span class="sr-only">Next</span>
                </a>

             <?php endif;  wp_reset_postdata(); ?>
          </div>

doesn't seem to work

The code works fine, just remove line 5 or add posts with the tag "slider".

This is awesome! I've been looking for a quick solution to something and this is the perfect fit. Thanks for putting it together and sharing :)