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 @ 07:51
Script: /attachment.php?attachmentid=70&sid=d2ec2c4c9ae4bb3f95add19b09659813
Referer: http://www.stc-board.de/attachment.php?attachmentid=70&sid=d2ec2c4c9ae4bb3f95add19b09659813