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: 11.05.2024 @ 19:53
Script: /memberslist.php?letter=&sid=79311ac2f47c25cf2eb1f3dcf20a1478&order=ASC&sortby=userposts&page=9
Referer: http://stc-board.de/memberslist.php?letter=&sid=79311ac2f47c25cf2eb1f3dcf20a1478&order=ASC&sortby=userposts&page=9