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: 06.05.2024 @ 16:00
Script: /usercp.php?action=buddy&add=291&sid=684707b9aa4f0b0b63266d955d5e54bd
Referer: http://stc-board.de/usercp.php?action=buddy&add=291&sid=684707b9aa4f0b0b63266d955d5e54bd