사이트 오류 문의..ㅠ

아래처럼 오류가 뜨는데 원인 알 수있을까요?ㅠ

Warning: Use of undefined constant G5_MYSQL_HOST - assumed 'G5_MYSQL_HOST' (this will throw an Error in a future version of PHP) in /host/home3/dohye1/html/common.php on line 135

Warning: Use of undefined constant G5_MYSQL_USER - assumed 'G5_MYSQL_USER' (this will throw an Error in a future version of PHP) in /host/home3/dohye1/html/common.php on line 135

Warning: Use of undefined constant G5_MYSQL_PASSWORD - assumed 'G5_MYSQL_PASSWORD' (this will throw an Error in a future version of PHP) in /host/home3/dohye1/html/common.php on line 135

Warning: Use of undefined constant G5_MYSQL_DB - assumed 'G5_MYSQL_DB' (this will throw an Error in a future version of PHP) in /host/home3/dohye1/html/lib/common.lib.php on line 1550

Warning: mysqli_connect(): php_network_getaddresses: getaddrinfo failed: Name or service not known in /host/home3/dohye1/html/lib/common.lib.php on line 1555

Warning: mysqli_connect(): (HY000/2002): php_network_getaddresses: getaddrinfo failed: Name or service not known in /host/home3/dohye1/html/lib/common.lib.php on line 1555
Connect Error: php_network_getaddresses: getaddrinfo failed: Name or service not known