Fatal error: Cannot use database usr_web21_1

You get more information about the problem in our knowledge base: http://www.woltlab.com/help/?code=1044

Information:

error message: Cannot use database usr_web21_1
error code: 1044
sql type: MySQLDatabase
sql error: Access denied for user 'web21'@'178.254.62.160' to database 'usr_web21_1'
sql error number: 1044
sql version:
file: /var/www/web21/html/wcf/lib/system/database/MySQLDatabase.class.php (57)
php version: 5.3.29
wcf version: 1.0.11 pl 1 (Horizon)
date: Wed, 01 Dec 2021 11:47:14 +0000
request: /
referer:

Stacktrace:

#0 /var/www/web21/html/wcf/lib/system/database/Database.class.php(79): MySQLDatabase->selectDatabase()
#1 /var/www/web21/html/wcf/lib/system/WCF.class.php(270): Database->__construct(...)
#2 /var/www/web21/html/wcf/lib/system/WCF.class.php(88): WCF->initDB()
#3 /var/www/web21/html/global.php(18): WCF->__construct()
#4 /var/www/web21/html/index.php(7): require_once('/var/www/web21/...')
#5 {main}