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: 10.05.2024 @ 15:26
Script: /board.php?boardid=56&sid=0f1e6b7fa834d3ce586ff724f2f63fbf
Referer: http://stc-board.de/board.php?boardid=56&sid=0f1e6b7fa834d3ce586ff724f2f63fbf