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 @ 01:32
Script: /board.php?boardid=29&page=1&daysprune=1000&sortfield=starter&sortorder=ASC&sid=f08d729a98a717fe3e1ec9c112c672cb
Referer: http://stc-board.de/board.php?boardid=29&page=1&daysprune=1000&sortfield=starter&sortorder=ASC&sid=f08d729a98a717fe3e1ec9c112c672cb