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 @ 00:57
Script: /thread.php?threadid=715&threadview=0&hilight=&hilightuser=0&sid=da4d339d2e027fa8a7a34af3566a537f&page=2
Referer: http://stc-board.de/thread.php?threadid=715&threadview=0&hilight=&hilightuser=0&sid=da4d339d2e027fa8a7a34af3566a537f&page=2