Normally I would suggest that there is a caching issue, if non-logged in users are seeing something different to logged in users. The solution there would be to clear the cache generated by a WP plugin or server level caching.
But as you’re getting the ‘Something’s wrong’ message that needs to be investigated. Would you mind sending me access details to your site via our secure contact form so I can see what’s going on?
(ideally creating a temporary user account for me with Administrator access which you can delete afterwards).