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 @ 04:46
Script: /calendar.php?sid=88c306814d8f48f77c6c4e8e52845fc7
Referer: