Notes
How to fix “Host ‘127.0.0.1’ is not allowed to connect to this MariaDB server.” in RubyMine Data Source
On server, run this command to enable translation of IP addresses to hostnames. Then restart the database server.
sudo sed -i 's/^skip-name-resolve/#skip-name-resolve/' /etc/mysql/mariadb.conf.d/50-server.cnf
sudo systemctl restart mysql