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 @ 00:20
Script: /memberslist.php?letter=&sid=44f03f2c4c724950bd11c16c52ed8f8f&sortby=msn&order=ASC
Referer: http://stc-board.de/memberslist.php?letter=&sid=44f03f2c4c724950bd11c16c52ed8f8f&sortby=msn&order=ASC