Error started in adminajax

Ive seen this happen when a Repeater Template may have some issues.
In the next ALM release this will not be a blocking issue as I plan to have this silently fail.

Can you share the Repeater Template?

sure thing

<div class="story">
            <a href="<?php the_permalink(); ?>">
                <?php $url = wp_get_attachment_url( get_post_thumbnail_id($post->ID) );
echo '<div class="thumb-image" style="background-image: url('. $url.')"></div>'; ?>
            </a>

            <div class="story-info">

                <?php get_template_part( 'template-parts/content', 'categories' ); ?>

                <a href="<?php the_permalink(); ?>">
                    <h3>
                        <?php the_title(); ?>
                    </h3>
                </a>
                <p>
                    <?php the_excerpt();?>
                </p>
                <h5>
                    <?php the_author(); ?>
                </h5>
            </div>
        </div>

Hmm looks fine.
I would start by debugging this template.
Maybe remove everything except for <h3><?php the_title(); ?></h3>

So weird, i just made a duplicate copy of the theme and initiated then it started working again?

I folowed the steps on this page and even ran with just the title like stated above and still didn’t work. Getting the following:

ajax-load-more.min.js?ver=5.4.3:6 Error:  Error: Network Error
    at t.exports (ajax-load-more.min.js?ver=5.4.3:6)
    at XMLHttpRequest.p.onerror (ajax-load-more.min.js?ver=5.4.3:6)
ajax-load-more.min.js?ver=5.4.3:6 XMLHttpRequest?{readyState: 4, timeout: 0, withCredentials: false, upload: XMLHttpRequestUpload, onreadystatechange: ?,?…}
ajax-load-more.min.js?ver=5.4.3:6 ALM Error started in adminajax
ajax-load-more.min.js?ver=5.4.3:6 ALM Error Debug: