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 @ 16:09
Script: /formmail.php?userid=4&sid=c13b7b63c4ec0e5c96ae1d1ef26c8bf0
Referer: http://stc-board.de/formmail.php?userid=4&sid=c13b7b63c4ec0e5c96ae1d1ef26c8bf0