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: 04.05.2024 @ 21:34
Script: /attachment.php?attachmentid=1165&sid=7c6ffcb9478ae5d6c19adc3539db0ba9
Referer: http://stc-board.de/attachment.php?attachmentid=1165&sid=7c6ffcb9478ae5d6c19adc3539db0ba9