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: 04.05.2024 @ 18:48
Script: /thread.php?threadid=731&threadview=0&hilight=&hilightuser=0&sid=224f42fb7d9543d4e0301f71105a0913&page=2
Referer: http://stc-board.de/thread.php?threadid=731&threadview=0&hilight=&hilightuser=0&sid=224f42fb7d9543d4e0301f71105a0913&page=2