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 @ 01:04
Script: /formmail.php?threadid=861&sid=2ef0be80d0edc835a1cc103f1025018b
Referer: http://stc-board.de/formmail.php?threadid=861&sid=2ef0be80d0edc835a1cc103f1025018b