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: 10.05.2024 @ 23:42
Script: /usercp.php?action=buddy&add=55&sid=98f8c77e08ca21feb526238951ee5fe8
Referer: http://stc-board.de/usercp.php?action=buddy&add=55&sid=98f8c77e08ca21feb526238951ee5fe8