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: 04.05.2024 @ 21:20
Script: /memberslist.php?letter=&sid=66377e0ef8bcb1445d0d30517dd0ee72&sortby=email&order=ASC
Referer: http://www.stc-board.de/memberslist.php?letter=&sid=66377e0ef8bcb1445d0d30517dd0ee72&sortby=email&order=ASC