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: 10.05.2024 @ 00:59
Script: /board.php?boardid=29&page=1&daysprune=1000&sortfield=starter&sortorder=ASC&sid=7ff693138f8c063f3444245a2f09cc7a
Referer: http://stc-board.de/board.php?boardid=29&page=1&daysprune=1000&sortfield=starter&sortorder=ASC&sid=7ff693138f8c063f3444245a2f09cc7a