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 @ 07:00
Script: /memberslist.php?letter=&sid=369e5dab20ee99db4b926dcb80884950&order=ASC&sortby=username&page=3
Referer: http://stc-board.de/memberslist.php?letter=&sid=369e5dab20ee99db4b926dcb80884950&order=ASC&sortby=username&page=3