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: 29.04.2024 @ 00:04
Script: /board.php?boardid=53&page=1&daysprune=1000&sortfield=lastposttime&sortorder=ASC&sid=46b3904c9d3645e2f18607e56198e849
Referer: http://stc-board.de/board.php?boardid=53&page=1&daysprune=1000&sortfield=lastposttime&sortorder=ASC&sid=46b3904c9d3645e2f18607e56198e849