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: 05.05.2024 @ 23:12
Script: /board.php?boardid=29&sid=dc3e119a63c5113f75b5aa50e0209dbe
Referer: http://stc-board.de/board.php?boardid=29&sid=dc3e119a63c5113f75b5aa50e0209dbe