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: 11.05.2024 @ 10:40
Script: /board.php?boardid=4&sid=d6e8efbadd2267ed3aeae07d8c78b927
Referer: http://stc-board.de/board.php?boardid=4&sid=d6e8efbadd2267ed3aeae07d8c78b927