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: 03.05.2024 @ 20:34
Script: /memberslist.php?letter=&sid=fd797b70c1ae55f9f4ebabf76dd8ba2d&sortby=msn&order=ASC
Referer: http://stc-board.de/memberslist.php?letter=&sid=fd797b70c1ae55f9f4ebabf76dd8ba2d&sortby=msn&order=ASC