SQL-DATABASE ERROR

Database error in WoltLab Burning Board (): Link-ID == false, connect failed
mysql error: Connection refused
mysql error number: 2002
mysql version: unknown
php version: 5.6.40-57+0~20211119.60+debian9~1.gbp8a9bd1
Date: 02.05.2024 @ 16:05
Script: /index.php?sid=a8bad6a81b0f1b6bfa167957c763615b
Referer: http://stc-board.de/index.php?sid=a8bad6a81b0f1b6bfa167957c763615b