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: 02.05.2024 @ 15:11
Script: /print.php?threadid=731&page=3&sid=4ae111be15b75aaf5dd73b930bcee27f
Referer: http://stc-board.de/print.php?threadid=731&page=3&sid=4ae111be15b75aaf5dd73b930bcee27f