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 @ 03:28
Script: /calendar.php?sid=9e746bc86996700b495f44305f9151f4
Referer: