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 @ 19:27
Script: /memberslist.php?letter=&sid=c6aab4d64f7645faf5e1cf1e58a2264e&sortby=username&order=ASC
Referer: http://stc-board.de/memberslist.php?letter=&sid=c6aab4d64f7645faf5e1cf1e58a2264e&sortby=username&order=ASC