Sorry for the delayed response. I’m unsure why we didn’t get back to you sooner. My apologies.
The admin-ajax.php throwing a 500 error means there’s likely some other issues going on at your site that’s causing this console error.
Please enable WP_DEBUG and WP_DEBUG_LOG (which will create a file on your server at /wp-content/debug.log if there are any WP_DEBUG messages) and share any debug messages you see while trying to replicate this issue and doing other things on your site relevant to this ticket (such as visiting your site’s home page, events page, single-event pages, and anything else you can think to do).
Please let me know what you find out.