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 @ 20:55
Script: /wbb2/calendar.php?sid=5d0cb570dc87e6fe79fcdbfd674d450b
Referer: http://www.friendsbistro.de/wbb2/calendar.php?sid=5d0cb570dc87e6fe79fcdbfd674d450b