When clicking "Preview" on post edit form, the displayed page contains the full header, the first breadcrumb item (home), and then breaks with "the site is experiencing technical difficulties". Nothing else is displayed.
If "breadcrumb" plugin is disabled, the problem disappears.
Apache log shows then:
AH01071: Got error 'PHP message: PHP Recoverable fatal error: Object of class WP_Error could not be converted to string in /var/www/vhosts/example.com/httpdocs/web/wp-content/plugins/breadcrumb/includes/class-shortcodes.php on line 115n', referer: https://www.example.com/web/wp-admin/post.php?post=60137&action=edit
WP Version 5.2.1
Plugin Version 1.5.1
PHP Version 7.2.18
Welcome to our forum.
Thanks for report this issue,
Can you please update the plugin to the latest version 1.5.2 and let me know the result.