WordPress Fatal error: Uncaught Error: syntax error

Solution:

You have some broken syntax in your code. You have a few <? when I believe you wanted <?php

I tried to clean it up for you so try this.

<?php
/**
 * The template for displaying Archive pages
 *
 * Used to display archive-type pages if nothing more specific matches a query.
 * For example, puts together date-based pages if no date.php file exists.
 *
 * If you'd like to further customize these archive views, you may create a
 * new template file for each specific one. For example, Twenty Fourteen
 * already has tag.php for Tag archives, category.php for Category archives,
 * and author.php for Author archives.
 *
 * @link https://developer.wordpress.org/themes/basics/template-hierarchy/
 *
 * @package WordPress
 * @subpackage Twenty_Fourteen
 * @since Twenty Fourteen 1.0
 */

get_header(); ?>

    <section id="primary" class="content-area">
        <div id="content" class="site-content" role="main">

            <?php if ( have_posts() ) : ?>

            <header class="page-header"><meta http-equiv="Content-Type" content="text/html; charset=utf-8">
                <h1 class="page-title">
                    <?php
                    if ( is_day() ) {
                        /* translators: %s: Date. */
                        printf( __( 'Daily Archives: %s', 'twentyfourteen' ), get_the_date() );
                    } elseif ( is_month() ) {
                        /* translators: %s: Date. */
                        printf( __( 'Monthly Archives: %s', 'twentyfourteen' ), get_the_date( _x( 'F Y', 'monthly archives date format', 'twentyfourteen' ) ) );
                    } elseif ( is_year() ) {
                        /* translators: %s: Date. */
                        printf( __( 'Yearly Archives: %s', 'twentyfourteen' ), get_the_date( _x( 'Y', 'yearly archives date format', 'twentyfourteen' ) ) );
                    } else {
                        _e( 'Archives', 'twentyfourteen' );
                    }
                    ?>
                </h1>
            </header><!-- .page-header -->
<section id="product-list" class="section">
            <div class="bandInner">
<?php
if ( function_exists('yoast_breadcrumb') ) {
yoast_breadcrumb('
<p id="breadcrumbs">','</p>
');
}

?>  <h1 class='pageTitle'><?php
    printf( __( ' %s', 'twentyten' ), '<span>' . single_cat_title( '', false ) . '</span>' );
?></h1>
<?php 
wp_nav_menu( array( 
    'theme_location' => 'product-category',
    'container'      => 'ul',
    'menu_class'     => 'prodCats',
) );

?>
<style>
ul.prodCats li{
    display:initial!important;
}
ul.prodCats li.current-menu-item a {
    color: #8b2131!important;
}
</style>
<article id="mainContent">

                    <ul id="prodList">
    <?php
                // Start the Loop.
                while ( have_posts() ) :
                    the_post();

                    /*
                     * Include the post format-specific template for the content. If you want
                     * to use this in a child theme, then include a file called content-___.php
                     * (where ___ is the post format) and that will be used instead.
                     */
                    ?>  
                    <li>
                    <div class="prodCtn">
                                    <a class="prodImgCtn prodLink" href="<?php echo get_permalink(); ?>">
                                        <?php 
                                        $img = wp_get_attachment_image_src( get_field('product_image'), "thumb_product" ); 
                                        ?>
                                        <img class="prodImg" src="<?php echo $img[0]; ?>"/>
                                    </a>
                                    <div class="prodCont">
                                        <a href="<?php echo get_permalink(); ?>" class="">
                                            <p class="prodHd"><?php the_title(); ?></p>
                                        </a>
                                        <p>
                                            <?php  
                                                $givchars = 350; 
                                                //$postgiv = the_field('product_description'); 
                                                $postgiv = get_field('product_description'); 
                                                $modgiv = substr($postgiv, 0, $givchars); 
                                                echo ' ' .$modgiv. '... ';
                                            ?>
                                        </p>
                                        <a href="<?php echo get_permalink(); ?>" class="btn">
                                            <span class="btnTxt">View More</span>
                                        </a>
                                    </div>
                                </div>
                                </li>
<?php

                    endwhile;?>
                    </ul>
                    <div id="show-hide-content" class="cat-content less-mode"><?php echo category_description(); ?></div>

                </article>

                    <?php
                    // Previous/next page navigation.


                endif;
                ?></div><!-- #content -->
    </section>
        </div><!-- #content -->
    </section><!-- #primary -->

<?php
get_footer();
?>