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: 11.05.2024 @ 19:35
Script: /memberslist.php?letter=&sid=39b1ca3d2a04a2d044f51d0f7fc1fcb0&sortby=homepage&order=ASC
Referer: http://stc-board.de/memberslist.php?letter=&sid=39b1ca3d2a04a2d044f51d0f7fc1fcb0&sortby=homepage&order=ASC