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: 02.05.2024 @ 22:36
Script: /board.php?boardid=4&daysprune=1000&sortfield=lastposttime&sortorder=DESC&page=7&sid=3cfb4b91fb6bf647a5cddede11c82e66
Referer: http://stc-board.de/board.php?boardid=4&daysprune=1000&sortfield=lastposttime&sortorder=DESC&page=7&sid=3cfb4b91fb6bf647a5cddede11c82e66