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: 06.05.2024 @ 00:30
Script: /attachment.php?attachmentid=240&sid=2aab8de1a764f02daa234dcfee185c7a
Referer: http://stc-board.de/attachment.php?attachmentid=240&sid=2aab8de1a764f02daa234dcfee185c7a