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: 01.05.2024 @ 09:05
Script: /usercp.php?action=buddy&add=74&sid=309b0ea79c4b0d7555a2ab9ea2098333
Referer: http://stc-board.de/usercp.php?action=buddy&add=74&sid=309b0ea79c4b0d7555a2ab9ea2098333