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: 09.05.2024 @ 23:04
Script: /board.php?boardid=28&page=1&daysprune=1000&sortfield=lastposttime&sortorder=ASC&sid=2462ff3018f0ddc7785d466255671f59
Referer: http://stc-board.de/board.php?boardid=28&page=1&daysprune=1000&sortfield=lastposttime&sortorder=ASC&sid=2462ff3018f0ddc7785d466255671f59