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 @ 07:17
Script: /wbb/usercp.php?action=addsubscription&boardid=143&sid=b25dc4d6a5f46b015e25d44f5cede7e0
Referer: http://www.delftseschaaksite.nl/wbb/usercp.php?action=addsubscription&boardid=143&sid=b25dc4d6a5f46b015e25d44f5cede7e0