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: 03.05.2024 @ 20:28
Script: /formmail.php?threadid=268&sid=d8ae4777dc8967d0e5294201518f3f8d
Referer: http://stc-board.de/formmail.php?threadid=268&sid=d8ae4777dc8967d0e5294201518f3f8d