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: 09.05.2024 @ 08:46
Script: /memberslist.php?letter=&sid=56a5e71439e9f8b289a9ad166fd18f88&sortby=gender&order=ASC
Referer: http://stc-board.de/memberslist.php?letter=&sid=56a5e71439e9f8b289a9ad166fd18f88&sortby=gender&order=ASC