Fatal error: Uncaught mysqli_sql_exception: Unknown error while trying to connect via (null) in /mnt/web214/b0/03/511258103/htdocs/STRATO-apps/wordpress_04/app/wp-includes/wp-db.php:1653
Stack trace:
#0 /mnt/web214/b0/03/511258103/htdocs/STRATO-apps/wordpress_04/app/wp-includes/wp-db.php(1653): mysqli_real_connect()
#1 /mnt/web214/b0/03/511258103/htdocs/STRATO-apps/wordpress_04/app/wp-includes/wp-db.php(632): wpdb->db_connect()
#2 /mnt/web214/b0/03/511258103/htdocs/STRATO-apps/wordpress_04/app/wp-content/plugins/query-monitor/wp-content/db.php(75): wpdb->__construct()
#3 /mnt/web214/b0/03/511258103/htdocs/STRATO-apps/wordpress_04/app/wp-content/plugins/query-monitor/wp-content/db.php(140): QM_DB->__construct()
#4 /mnt/web214/b0/03/511258103/htdocs/STRATO-apps/wordpress_04/app/wp-includes/load.php(546): require_once('...')
#5 /mnt/web214/b0/03/511258103/htdocs/STRATO-apps/wordpress_04/app/wp-settings.php(124): require_wp_db()
#6 /mnt/web214/b0/03/511258103/htdocs/STRATO-apps/wordpress_04/app/wp-config.php(120): require_once('...')
#7 /mnt/web214/b0/03/511258103/htdocs/STRATO-apps/wordpress_04/app/wp-load.php(50): require_once('...')
#8 /mnt/web214/b0/03/511258103/htdocs/STRATO-apps/wordpress_04/app/wp-blog-header.php(13): require_once('...')
#9 /mnt/web214/b0/03/511258103/htdocs/STRATO-apps/wordpress_04/app/index.php(17): require('...')
#10 {main}
  thrown in /mnt/web214/b0/03/511258103/htdocs/STRATO-apps/wordpress_04/app/wp-includes/wp-db.php on line 1653