やりたい事：MailServiceクラスの拡張。

エラー発生：MailServiceをextendsし読込時

エラー詳細：__construct内の下記実行時に落ちます。
$this->BaseInfo = $baseInfoRepository->get();

■エラー内容
In AbstractMySQLDriver.php line 93:

An exception occurred in driver: SQLSTATE[HY000] [2002] php_network_getaddresses: getaddrinfo failed: nodename nor servname provided, or not known


In PDOConnection.php line 31:

SQLSTATE[HY000] [2002] php_network_getaddresses: getaddrinfo failed: nodename nor servname provided, or not known


In PDOConnection.php line 27:

SQLSTATE[HY000] [2002] php_network_getaddresses: getaddrinfo failed: nodename nor servname provided, or not known


In PDOConnection.php line 27:

PDO::__construct(): php_network_getaddresses: getaddrinfo failed: nodename nor servname provided, or not known

ご協力お願い致します。