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: 07.05.2024 @ 07:55
Script: /calendar.php?action=eventcalendar&sid=1f6a1009de6b6af530936d62d8d1c1a8
Referer: http://stc-board.de/calendar.php?action=eventcalendar&sid=1f6a1009de6b6af530936d62d8d1c1a8