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: 5.6.40-70+0~20240421.84+debian12~1.gbp0c0ec4
Date: 27.07.2024 @ 09:00
Script: /usercp.php?action=addsubscription&boardid=44&sid=126b477fb3d11cd8bd38d85785e127b8
Referer: