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: 05.05.2024 @ 22:50
Script: /usercp.php?action=buddy&add=74&sid=f2eaa3ccc00b4e72d1aace969611202d
Referer: http://stc-board.de/usercp.php?action=buddy&add=74&sid=f2eaa3ccc00b4e72d1aace969611202d