SQL-DATABASE ERROR

Database error in WoltLab Burning Board (): Link-ID == false, connect failed
mysql error: No such file or directory
mysql error number: 2002
mysql version: unknown
php version: 5.6.40-65+0~20230409.73+debian10~1.gbp473a1b
Date: 14.05.2024 @ 18:51
Script: /usercp.php?action=buddy&add=88&sid=0cc32f29d9ae895664db330a62dea6ea
Referer: