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: 28.04.2024 @ 09:58
Script: /board.php?boardid=55&page=1&daysprune=1000&sortfield=starter&sortorder=ASC&sid=5d67baa10ce718235d3b568981c0e533
Referer: http://stc-board.de/board.php?boardid=55&page=1&daysprune=1000&sortfield=starter&sortorder=ASC&sid=5d67baa10ce718235d3b568981c0e533