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: 05.05.2024 @ 18:03
Script: /profile.php?userid=20&sid=7670c6401dbdef2bc11f1b68c9fc21de
Referer: http://stc-board.de/profile.php?userid=20&sid=7670c6401dbdef2bc11f1b68c9fc21de