To delimite the problem:
Check MySQL/MariaDB it's running in the host.
ps axu|grep mysql
ps axu|grep mysql
root 12832 0.0 0.0 23068 3456 ? S mar01 0:00 /bin/bash /usr/bin/mysqld_safe
mysql 12967 0.1 0.9 613220 76684 ? Sl mar01 10:49 /usr/sbin/mysqld --basedir=/usr --datadir=/var/lib/mysql --plugin-dir=/usr/lib/mysql/plugin --user=mysql --skip-log-error --pid-file=/var/run/mysqld/mysqld.pid --socket=/var/run/mysqld/mysqld.sock --port=3306
Check the username Bacula exists in the Catalog Server (on mysql prompt = use mysql; select * from user where User='bacula';)
Check the username Bacula has the right permissions to access the bacula database.
If you run the make_bacula_database, make_bacula_tables and grant_bacula_privileges scripts maybe would be safe to set a password to the user bacula and configure it into the bacula-dir.conf too.
J.