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: 09.05.2024 @ 23:30
Script: /board.php?boardid=18&sid=31cbef87cc8fac218c9f27d1ca4b38ae
Referer: http://stc-board.de/board.php?boardid=18&sid=31cbef87cc8fac218c9f27d1ca4b38ae