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: 12.05.2024 @ 01:40
Script: /board.php?boardid=4&daysprune=1000&sortfield=lastposttime&sortorder=DESC&sid=574d71b5a2001bb16aa2f8e805018812&page=2
Referer: http://stc-board.de/board.php?boardid=4&daysprune=1000&sortfield=lastposttime&sortorder=DESC&sid=574d71b5a2001bb16aa2f8e805018812&page=2