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 @ 00:38
Script: /calendar.php?sid=668a04ac0132614c7c8cd4bd36e87f04
Referer: http://stc-board.de/calendar.php?sid=668a04ac0132614c7c8cd4bd36e87f04