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 @ 14:03
Script: /usercp.php?action=buddy&add=225&sid=cf266cc748f52fa3368d1200409b7d14
Referer: http://stc-board.de/usercp.php?action=buddy&add=225&sid=cf266cc748f52fa3368d1200409b7d14