SQL-DATABASE ERROR

Database error in WoltLab Burning Board (): Link-ID == false, connect failed
mysql error: php_network_getaddresses: getaddrinfo failed: Name or service not known
mysql error number: 2002
mysql version: unknown
php version: 5.6.33
Date: 17.01.2018 @ 11:19
Script: /wbb2/index.php
Referer: