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: 09.05.2024 @ 17:47
Script: /register.php?sid=a19d68cfcbc961260a50c7c0c91304ea
Referer: http://stc-board.de/register.php?sid=a19d68cfcbc961260a50c7c0c91304ea