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 @ 05:53
Script: /wbb/usercp.php?action=addsubscription&boardid=156&sid=ab0456c5889d6f1547732c02727ad5dd
Referer: http://delftseschaaksite.nl/wbb/usercp.php?action=addsubscription&boardid=156&sid=ab0456c5889d6f1547732c02727ad5dd