==> /var/log/nginx/ws.error.log <==
2019/01/18 14:00:14 [error] 7717#0: *164 FastCGI sent in stderr: "PHP message: PHP Fatal error: Uncaught Error: Class 'DOMDocument' not found in /var/www/html/wordpress/wp-content/plugins/encyclopedia-lexicon-glossary-wiki-dictionary/classes/cross-linker.ph" while reading upstream, client: 10.172.16.10, server: 10.172.16.5, request: "GET / HTTP/1.0", upstream: "fastcgi://unix:/var/run/php-fpm/php-fpm.sock:", host: "example.net", referrer: "https://example.net/encyclopedia/"
2019/01/18 14:00:14 [error] 7717#0: *164 FastCGI sent in stderr: "p:23
Stack trace:
#0 /var/www/html/wordpress/wp-content/plugins/encyclopedia-lexicon-glossary-wiki-dictionary/classes/core.php(79): WordPress\Plugin\Encyclopedia\Cross_Linker->loadContent('<?xml encoding=...')
#1 /var/www/html/wordpress/wp-content/plugins/encyclopedia-lexicon-glossary-wiki-dictionary/classes/content-filter.php(52): WordPress\Plugin\Encyclopedia\Core::addCrossLinks('<p style="text-...', Object(WP_Post))
#2 /var/www/html/wordpress/wp-includes/class-wp-hook.php(286): WordPress\Plugin\Encyclopedia\Content_Filter::addCrossLinks('<p style="text-...')
#3 /var/www/html/wordpress/wp-includes/plugin.php(203): WP_Hook->apply_filters('<p style="text-...', Array)
#4 /var/www/html/wordpress/wp-includes/post-template.php(240): apply_filters('the_content', '<p style="text-...')
#5 /var/www/html/wordpress/wp-content/" while reading upstream, client: 10.172.16.10, server: 10.172.16.5, request: "GET / HTTP/1.0", upstream: "fastcgi://unix:/var/run/php-fpm/php-fpm.sock:", host: "example.net", referrer: "https://example.net/encyclopedia/"