Just after installing MariaDB on Ubuntu / Debian, this error may appear if you try to connect with phpMyadmin.
To solve / work around the problem, we will create another user with the same level of rights as root.
1. Open an SSH connection on the server.
2. Enter the following commands:
mysql
CREATE USER 'admin'@'%' IDENTIFIED BY 'password';
GRANT ALL PRIVILEGES ON *.* TO 'admin'@'%' WITH GRANT OPTION;
FLUSH PRIVILEGES;
exit;3. Restart the MariaDB service.
It is now possible to connect with the admin user on phpMyadmin