SQL-DATABASE ERROR

Database error in (): Link-ID == false, connect failed
mysql error:
mysql error number:
mysql version: unknown
php version: 7.4.33
Date: 22.05.2024 @ 04:32
Script: /wbb2/calendar.php?sid=83277fa6b60b6befb83a96d9942c8f53
Referer: http://www.friendsbistro.de/wbb2/calendar.php?sid=83277fa6b60b6befb83a96d9942c8f53