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 @ 01:26
Script: /board.php?boardid=52&sid=6fc34fbc7ff1bf1a0c51a803b8429d07
Referer: http://stc-board.de/board.php?boardid=52&sid=6fc34fbc7ff1bf1a0c51a803b8429d07