Warning: include(/var/www/vhosts/suedhang.ch/httpdocs/wp-content/plugins/wordpress-seo/vendor/composer/../../lib/abstract-main.php): failed to open stream: No such file or directory in /var/www/vhosts/suedhang.ch/httpdocs/wp-content/plugins/duplicate-post/vendor/composer/ClassLoader.php on line 571

Warning: include(): Failed opening '/var/www/vhosts/suedhang.ch/httpdocs/wp-content/plugins/wordpress-seo/vendor/composer/../../lib/abstract-main.php' for inclusion (include_path='.:/usr/share/pear:/usr/share/php') in /var/www/vhosts/suedhang.ch/httpdocs/wp-content/plugins/duplicate-post/vendor/composer/ClassLoader.php on line 571

Fatal error: Uncaught Error: Class 'Yoast\WP\Lib\Abstract_Main' not found in /var/www/vhosts/suedhang.ch/httpdocs/wp-content/plugins/wordpress-seo/src/main.php:25
Stack trace:
#0 /var/www/vhosts/suedhang.ch/httpdocs/wp-content/plugins/duplicate-post/vendor/composer/ClassLoader.php(571): include()
#1 /var/www/vhosts/suedhang.ch/httpdocs/wp-content/plugins/duplicate-post/vendor/composer/ClassLoader.php(428): Composer\Autoload\includeFile('/var/www/vhosts...')
#2 [internal function]: Composer\Autoload\ClassLoader->loadClass('Yoast\\WP\\SEO\\Ma...')
#3 /var/www/vhosts/suedhang.ch/httpdocs/wp-content/plugins/wordpress-seo/src/functions.php(33): spl_autoload_call('Yoast\\WP\\SEO\\Ma...')
#4 /var/www/vhosts/suedhang.ch/httpdocs/wp-content/plugins/wordpress-seo/wp-seo-main.php(445): YoastSEO()
#5 /var/www/vhosts/suedhang.ch/httpdocs/wp-content/plugins/wordpress-seo/wp-seo.php(50): require_once('/var/www/vhosts...')
#6 /var/www/vhosts/suedhang.ch/httpdocs/wp-settings.php(526): include_once('/var/www/vhosts...')
#7 /var/www/vhosts/ in /var/www/vhosts/suedhang.ch/httpdocs/wp-content/plugins/wordpress-seo/src/main.php on line 25