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 @ 08:26
Script: /calendar.php?sid=ad3987a1a8dbd6094f6e4aca2beaefdb
Referer: http://stc-board.de/calendar.php?sid=ad3987a1a8dbd6094f6e4aca2beaefdb