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 @ 22:06
Script: /calendar.php?sid=6e7a32e71397e63f47c42a1f8c31b4ef
Referer: http://stc-board.de/calendar.php?sid=6e7a32e71397e63f47c42a1f8c31b4ef