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 @ 01:32
Script: /board.php?boardid=53&sid=629f5a7a21a5e2b18a33ceb2d0aeaa33
Referer: http://www.stc-board.de/board.php?boardid=53&sid=629f5a7a21a5e2b18a33ceb2d0aeaa33