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 @ 00:28
Script: /thread.php?threadid=729&threadview=1&hilight=&hilightuser=0&sid=4c1c9d073b1adffcb919b55cc19f3d95
Referer: http://stc-board.de/thread.php?threadid=729&threadview=1&hilight=&hilightuser=0&sid=4c1c9d073b1adffcb919b55cc19f3d95