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 @ 20:27
Script: /calendar.php?sid=18307477dd02e7e6dddc63f749abae51
Referer: http://stc-board.de/calendar.php?sid=18307477dd02e7e6dddc63f749abae51