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: 30.04.2024 @ 20:16
Script: /board.php?boardid=18&page=1&daysprune=1000&sortfield=views&sortorder=ASC&sid=ca129afc7c5a2054f01e8468dc49f23c
Referer: http://stc-board.de/board.php?boardid=18&page=1&daysprune=1000&sortfield=views&sortorder=ASC&sid=ca129afc7c5a2054f01e8468dc49f23c