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: 05.05.2024 @ 00:57
Script: /register.php?sid=708f2cb26d15591e8e775c3bb42b18a4
Referer: http://stc-board.de/register.php?sid=708f2cb26d15591e8e775c3bb42b18a4