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: 07.05.2024 @ 01:32
Script: /memberslist.php?letter=&sid=b704f5a2f29a2540d96ad3b1ce58d186&order=ASC&sortby=msn&page=3
Referer: http://stc-board.de/memberslist.php?letter=&sid=b704f5a2f29a2540d96ad3b1ce58d186&order=ASC&sortby=msn&page=3