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: 04.05.2024 @ 07:58
Script: /calendar.php?sid=32b7c02fbba70213e84a0763d73d9550
Referer: http://stc-board.de/calendar.php?sid=32b7c02fbba70213e84a0763d73d9550