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: 07.05.2024 @ 01:46
Script: /board.php?boardid=52&sid=2766f6e4c2ee644fc121951c9f8f9152
Referer: http://stc-board.de/board.php?boardid=52&sid=2766f6e4c2ee644fc121951c9f8f9152