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: 09.05.2024 @ 18:10
Script: /calendar.php?sid=4f4510527d903b1584f6ef206d0c973f
Referer: http://stc-board.de/calendar.php?sid=4f4510527d903b1584f6ef206d0c973f