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: 02.05.2024 @ 22:22
Script: /thread.php?threadid=380&threadview=0&hilight=&hilightuser=0&page=1&sid=09f93fb834f13951c79b54eef7c9a68d
Referer: http://stc-board.de/thread.php?threadid=380&threadview=0&hilight=&hilightuser=0&page=1&sid=09f93fb834f13951c79b54eef7c9a68d