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 @ 00:12
Script: /calendar.php?sid=35a07f847a30ec0fff086d9a114803af
Referer: http://stc-board.de/calendar.php?sid=35a07f847a30ec0fff086d9a114803af