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: 29.04.2024 @ 01:32
Script: /usercp.php?action=buddy_list&sid=471fffe2beaeb0d6cb68a2d392c2d4ff
Referer: http://stc-board.de/usercp.php?action=buddy_list&sid=471fffe2beaeb0d6cb68a2d392c2d4ff