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 @ 01:49
Script: /wbb/usercp.php?action=addsubscription&boardid=21&sid=f6c3c568d02c57d16fdce48fc78f095d
Referer: http://delftseschaaksite.nl/wbb/usercp.php?action=addsubscription&boardid=21&sid=f6c3c568d02c57d16fdce48fc78f095d