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 @ 10:40
Script: /login.php?sid=d7506dd6b67c5b15b9abe9f4e62ffa6b
Referer: http://stc-board.de/login.php?sid=d7506dd6b67c5b15b9abe9f4e62ffa6b