Fatal error: Uncaught PDOException: PDO::__construct(): php_network_getaddresses: getaddrinfo for db failed: Name or service not known in /var/www/html/includes/db.php:18 Stack trace: #0 /var/www/html/includes/db.php(18): PDO->__construct('mysql:host=db;d...', 'kan', Object(SensitiveParameterValue), Array) #1 /var/www/html/guestbook/index.php(40): db() #2 {main} Next PDOException: SQLSTATE[HY000] [2002] php_network_getaddresses: getaddrinfo for db failed: Name or service not known in /var/www/html/includes/db.php:18 Stack trace: #0 /var/www/html/includes/db.php(18): PDO->__construct('mysql:host=db;d...', 'kan', Object(SensitiveParameterValue), Array) #1 /var/www/html/guestbook/index.php(40): db() #2 {main} thrown in /var/www/html/includes/db.php on line 18