MultiDB

Problem:

You can not add new domains when multi-database is enabled.

Failed to create multi-db database. See error log for more.

Cause:

This usually happens because the MySQL user stored in the multidb-list.php file does not have privileges to create a new database.

Solution:

Execute this MySQL query, with your actual username (root in this case) and password:

CREATE USER IF NOT EXISTS `root`@`%` IDENTIFIED BY 'yourpass';
GRANT ALL PRIVILEGES ON *.* TO `root`@`%` IDENTIFIED BY 'yourpass';

The user needs all privileges on wildcard database names, because it has to be able to create new a new database for the newly added domain.