SQL-DATABASE ERROR

Database error in WoltLab Burning Board (): Link-ID == false, connect failed
mysql error: php_network_getaddresses: getaddrinfo failed: Temporary failure in name resolution
mysql error number: 2002
mysql version: unknown
php version: 5.6.40
Date: 30.11.2021 @ 04:57
Script: /calendar.php?sid=869c85eba0bbd77bbfb87b37ab53e231
Referer: