Fatal error: Connecting to MySQL server 'localhost' failed.

You get more information about the problem in our knowledge base: http://www.woltlab.com/help/?code=2002

Information:

error message: Connecting to MySQL server 'localhost' failed.
error code: 2002
sql type: MySQLDatabase
sql error: Can't connect to local MySQL server through socket '/home/webuser/mariadb/tmp/mysqld.sock' (111)
sql error number: 2002
sql version:
file: /home/webuser/www/de.schnatterkiste/wcf/lib/system/database/MySQLDatabase.class.php (29)
php version: 5.6.36-0+deb8u1
wcf version: 1.0.7
date: Thu, 20 Sep 2018 03:32:18 +0000
request: /index.php?page=Board&boardID=42&s=aa81cbfb3ab3648151502bf98efbbeb7c2bcdc4e
referer:

Stacktrace:

#0 /home/webuser/www/de.schnatterkiste/wcf/lib/system/database/Database.class.php(76): MySQLDatabase->connect()
#1 /home/webuser/www/de.schnatterkiste/wcf/lib/system/WCF.class.php(270): Database->__construct(...)
#2 /home/webuser/www/de.schnatterkiste/wcf/lib/system/WCF.class.php(88): WCF->initDB()
#3 /home/webuser/www/de.schnatterkiste/global.php(18): WCF->__construct()
#4 /home/webuser/www/de.schnatterkiste/index.php(7): require_once('/home/webuser/w...')
#5 {main}