Running Centos 7 with MariaDB 10.2.9 and trying to access the database from an external client

Error message: Host 'xxx.xx.xxx.xxx' is not allowed to connect to this MariaDB server

Found this instruction: https://help.directadmin.com/item.php?id=690

Suggests this sql command:
ALTER TABLE mysql.user ALTER authentication_string SET DEFAULT '';
But it gave an error message.

What I needed to do instead:
ALTER TABLE `user` CHANGE `authentication_string` `authentication_string` TEXT CHARACTER SET utf8 COLLATE utf8_bin NULL DEFAULT '\'\'';

Maybe helpfull for someone with the same issue