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: 29.04.2024 @ 00:04
Script: /thread.php?threadid=247&threadview=0&hilight=&hilightuser=0&page=251&sid=b530e040af2b8b0b1ff84ca660fd0adc
Referer: http://stc-board.de/thread.php?threadid=247&threadview=0&hilight=&hilightuser=0&page=251&sid=b530e040af2b8b0b1ff84ca660fd0adc