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 @ 00:54
Script: /newthread.php?boardid=53&sid=4abc4908647b98f7c1e95d5b8bfa2468
Referer: http://stc-board.de/newthread.php?boardid=53&sid=4abc4908647b98f7c1e95d5b8bfa2468