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 @ 23:11
Script: /memberslist.php?letter=&sid=08929e7b3f8fe7a6a5e3b86a1b934f80&sortby=gender&order=ASC
Referer: http://stc-board.de/memberslist.php?letter=&sid=08929e7b3f8fe7a6a5e3b86a1b934f80&sortby=gender&order=ASC