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 @ 18:46
Script: /register.php?sid=8db3350d239e34ca85f878fceb9af1eb
Referer: http://stc-board.de/register.php?sid=8db3350d239e34ca85f878fceb9af1eb