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 @ 08:04
Script: /usercp.php?action=buddy&add=33&sid=f38e046f9d1a0b3a8507aed354da7ab4
Referer: http://stc-board.de/usercp.php?action=buddy&add=33&sid=f38e046f9d1a0b3a8507aed354da7ab4