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: 10.05.2024 @ 12:31
Script: /calendar.php?sid=83151ff8a5bf66d3ed3a5d35f6176ec5
Referer: http://stc-board.de/calendar.php?sid=83151ff8a5bf66d3ed3a5d35f6176ec5