Fatal error: Connecting to MySQL server '' failed.

Information:

error message: Connecting to MySQL server '' failed.
error code: 0
sql type: MySQLiDatabase
sql error:
sql error number:
sql version:
file: /home/www/youngbiker.de/html/wcf/lib/system/database/MySQLiDatabase.class.php (26)
php version: 7.4.33
wcf version: 1.0.11 (Horizon)
date: Mon, 17 Jun 2024 07:47:59 +0000
request: /wbboard/index.php?form=MembersSearch&s=c7515a6d5fb06211fa975ec2d43fd1496ab5ba5e
referer:

Stacktrace:

#0 /home/www/youngbiker.de/html/wcf/lib/system/database/Database.class.php(76): MySQLiDatabase->connect()
#1 /home/www/youngbiker.de/html/wcf/lib/system/WCF.class.php(266): Database->__construct(...)
#2 /home/www/youngbiker.de/html/wcf/lib/system/WCF.class.php(88): WCF->initDB()
#3 /home/www/youngbiker.de/html/wbboard/global.php(18): WCF->__construct()
#4 /home/www/youngbiker.de/html/wbboard/index.php(33): require_once('/home/www/young...')
#5 {main}