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: 08.05.2024 @ 00:35
Script: /board.php?boardid=52&page=1&daysprune=1000&sortfield=replycount&sortorder=ASC&sid=ca948b78f1a800fa8b6dadc94d825eda
Referer: http://stc-board.de/board.php?boardid=52&page=1&daysprune=1000&sortfield=replycount&sortorder=ASC&sid=ca948b78f1a800fa8b6dadc94d825eda