SQL-DATABASE ERROR

Database error in WoltLab Burning Board: Link-ID == false, connect failed
mysql error: Can't connect to local MySQL server through socket '/var/run/mysqld/mysqld.sock' (2)
mysql error number: 2002
Date: 21.05.2024 @ 08:33
Script: /wbb/usercp.php?action=addsubscription&boardid=151&sid=f96218ed82c79f1a1a0ae95f63d25e98
Referer: http://www.delftseschaaksite.nl/wbb/usercp.php?action=addsubscription&boardid=151&sid=f96218ed82c79f1a1a0ae95f63d25e98