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: 03.05.2024 @ 18:24
Script: /calendar.php?sid=ad0ab1c7e428270bf4f42b4b30fe42cf
Referer: http://stc-board.de/calendar.php?sid=ad0ab1c7e428270bf4f42b4b30fe42cf