SQL-DATABASE ERROR

Database error in WoltLab Burning Board (2.3.6): Link-ID == false, connect failed
mysql error: No such file or directory
mysql error number: 2002
mysql version: unknown
php version: 5.6.40-nmm8
Date: 16.05.2024 @ 05:30
Script: /xforum/register.php?sid=f0fbcaaf8539a0503c416b021b0eb2fb
Referer: