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: 16.05.2024 @ 01:34
Script: /wbb2/calendar.php?sid=c9f1d187f6f9d2e4f4d86933d2ef1ab5
Referer: