Note:I uses 000webhost.com's phpmyadmin My coding is

CREATE USER 'monty'@'localhost' IDENTIFIED BY 'some_pass';
GRANT ALL PRIVILEGES ON *.* TO 'monty'@'localhost'
        WITH GRANT OPTION;
 CREATE USER 'monty'@'%' IDENTIFIED BY 'some_pass';
 GRANT ALL PRIVILEGES ON *.* TO 'monty'@'%'
        WITH GRANT OPTION;

And my error is

1227 - Access denied; you need the CREATE USER privilege for this operation

make sure you have the correct db configuraion:

define('DB_HOST', 'mysq--.000webhost.com');