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: 02.05.2024 @ 20:09
Script: /memberslist.php?sid=9d418604a7d7f4f8565505599ac6264d
Referer: http://www.stc-board.de/memberslist.php?sid=9d418604a7d7f4f8565505599ac6264d