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: 30.04.2024 @ 05:39
Script: /register.php?sid=a8b7d0adc7ee7affd8bf90ea81d10b3b
Referer: http://stc-board.de/register.php?sid=a8b7d0adc7ee7affd8bf90ea81d10b3b