SQL-DATABASE ERROR

Database error in WoltLab Burning Board (): Link-ID == false, connect failed
mysql error: Unknown MySQL server host 'db2541.1und1.de' (-2)
mysql error number: 2005
mysql version: unknown
php version: 5.2.17
Date: 08.05.2024 @ 20:37
Script: /usercp.php?action=buddy&add=345&sid=4478ea5852d7f15c6cc5ed2d23201afe
Referer: