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: 01.05.2024 @ 00:05
Script: /thread.php?goto=lastpost&threadid=139&sid=14519d27d96e1381c4e3b8adc35c55db
Referer: http://stc-board.de/thread.php?goto=lastpost&threadid=139&sid=14519d27d96e1381c4e3b8adc35c55db