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 @ 01:10
Script: /memberslist.php?letter=&sid=89aa9ecf547a7164914840f6fbf88067&order=ASC&sortby=ranktitle&page=3
Referer: http://stc-board.de/memberslist.php?letter=&sid=89aa9ecf547a7164914840f6fbf88067&order=ASC&sortby=ranktitle&page=3